The amount of a radioactive material (having a half life of 100 years) remaining after 400 years will be __________ of its original weight. (A) 1/2 (B) 1/4 (C) 1/8 (D) 1/16

The amount of a radioactive material (having a half life of 100 years)
remaining after 400 years will be __________ of its original weight.
(A) 1/2
(B) 1/4
(C) 1/8
(D) 1/16
by

1 Answer

Answer :

(D) 1/16
by

Related questions

The half life period of a radioactive element is 100 days. After 400 days, one gm of the element will be reduced to __________ gm. (A) 1/4 (B) 1/8 (C) 1/2 (D) 1/16

Description : The half life period of a radioactive element is 100 days. After 400 days, one gm of the element will be reduced to __________ gm. (A) 1/4 (B) 1/8 (C) 1/2 (D) 1/16

Last Answer : (D) 1/16

The time taken for a radioactive element to reduce to 50% of its original weight is __________ years, if its half life period is 12 years. (A) 24 (B) 18 (C) 6 (D) 36

Description : The time taken for a radioactive element to reduce to 50% of its original weight is __________ years, if its half life period is 12 years. (A) 24 (B) 18 (C) 6 (D) 36

Last Answer : (B) 18

The activity of a radioactive element reduces to `(1//16)th` of its original value in 30 years. Find its half life?

Description : The activity of a radioactive element reduces to `(1//16)th` of its original value in 30 years. Find its half life?

Last Answer : The activity of a radioactive element reduces to `(1//16)th` of its original value in 30 years. Find its half ... B. 75 trs C. 7.5 day D. 75 month

The amount of a radioisotope remaining undecayed after a time equal to four times its half life, will be __________ percent. (A) 3.125 (B) 6.25 (C) 12.50 (D) 25

Description : The amount of a radioisotope remaining undecayed after a time equal to four times its half life, will be __________ percent. (A) 3.125 (B) 6.25 (C) 12.50 (D) 25

Last Answer : (B) 6.25

The half life of radioactive isotope is 3 hour. If the initial mass of isotope were 256 g, the mass of it remaining undecayed after 18 hr is a)12 g b)

Description : The half life of radioactive isotope is 3 hour. If the initial mass of isotope were 256 g, the mass of it remaining undecayed after 18 hr is a)12 g b)

Last Answer : The half life of radioactive isotope is 3 hour. If the initial mass of isotope were 256 g, the mass of it remaining ... 4 g B. 8 g C. 12 g D. 16 g

Initial amount of the radioactive element with half life 10 days is 16 g. What amount in gm of this element will remain after 40 days?

Description : Initial amount of the radioactive element with half life 10 days is 16 g. What amount in gm of this element will remain after 40 days?

Last Answer : Initial amount of the radioactive element with half life 10 days is 16 g. What amount in gm of this element will remain after 40 days?

A radioactive isotope has a half-life of 10 days. If today there are 125 g of it left, what was its original weight...

Description : A radioactive isotope has a half-life of 10 days. If today there are 125 g of it left, what was its original weight 40 days earlier  (a) 600 g (b) 1000 g (c) 1250 g (d) 2000 g 

Last Answer : Half life = 10days  The formula which is, 1/(2)^n × original weight = Weight left today.  To obtain the value of n = divide no of days by half life ie.,n= 40/10= 4 n=4 So, 1/(2)^n × original Weight = 125g 1/(2)^4 × Original weight = 125 Original weight = 16×125 = 2000g

Pick out the wrong statement. (A) α-particle emission from a radioactive element makes it electrically negative (B) β-particle emission from a radioactive element makes it electrically positive (C) A radioactive element having a half life period of 20 years will completely disintegrated in 40 years (D) The disintegration constant of a radioactive isotope is independent of pressure, temperature or concentration

Description : Pick out the wrong statement. (A) α-particle emission from a radioactive element makes it electrically negative (B) β-particle emission from a radioactive element makes it electrically ... ) The disintegration constant of a radioactive isotope is independent of pressure, temperature or concentration

Last Answer : (C) A radioactive element having a half life period of 20 years will completely disintegrated in 40 years

The half life of a radioactive element is 8-days. How long it take to reduce it from 10 mg to 5 mg? A. 4 days B. 12 days C. 16 days D. 8 days (Answer) E. None of these

Description : The half life of a radioactive element is 8-days. How long it take to reduce it from 10 mg to 5 mg? A. 4 days B. 12 days C. 16 days D. 8 days (Answer) E. None of these

Last Answer : D. 8 days (Answer)

The physical half life of radioactive 131I is: A. 8 hours B. 8 days C. 16 days D. 60 day

Description : The physical half life of radioactive 131I is: A. 8 hours B. 8 days C. 16 days D. 60 day

Last Answer : . 8 days

260 g of wet soil was taken in a pycnometer jar of weight 400 g in order to find the moisture content in the soil, with specific gravity of soil particles 2.75. The weight of soil and remaining water filled in pycnometer without air bubbles was 1415 g and the weight of pycnometer filled with water alone was 1275 g. The moisture content in the soil is (A) 24.2 % (B) 18.2 % (C) 53.8 % (D) None of these

Description : 260 g of wet soil was taken in a pycnometer jar of weight 400 g in order to find the moisture content in the soil, with specific gravity of soil particles 2.75. The weight of soil and remaining water filled in pycnometer without air ... is (A) 24.2 % (B) 18.2 % (C) 53.8 % (D) None of these

Last Answer : Answer: Option B

`""^(226)Ra` disintegrates at such a rate that after 3160 years, only one fourth of its original amount remains . The half life of `""^(226)Ra` will b

Description : `""^(226)Ra` disintegrates at such a rate that after 3160 years, only one fourth of its original amount remains . The half life of `""^(226)Ra` will b

Last Answer : `""^(226)Ra` disintegrates at such a rate that after 3160 years, only one fourth of its original amount ... B. 3160 years C. 1580 years D. 6230 years

The half life period of a radioactive element depends on its (A) Temperature (B) Pressure (C) Amount (D) None of these

Description : The half life period of a radioactive element depends on its (A) Temperature (B) Pressure (C) Amount (D) None of these

Last Answer : (D) None of these

The original cost of an equipment is Rs.10,000. Its salvage value at the end of its total useful life of five years is Rs. 1,000. Its book value at the end of two years of its useful life (as per straight line method of evaluation of depreciation) will be (A) Rs. 8,800 (B) Rs. 7,600 (C) Rs. 6,400 (D) Rs. 5,000

Description : The original cost of an equipment is Rs.10,000. Its salvage value at the end of its total useful life of five years is Rs. 1,000. Its book value at the end of two years of its useful life (as per straight line method of evaluation ... be (A) Rs. 8,800 (B) Rs. 7,600 (C) Rs. 6,400 (D) Rs. 5,000

Last Answer : (C) Rs. 6,400

If the half-life of a radioisotope is 2 days, after how many days is the quantity reduced to 12.5% of its original amount? w) 4 days x) 6 days y) 8 days z) 10 days

Description : If the half-life of a radioisotope is 2 days, after how many days is the quantity reduced to 12.5% of its original amount? w) 4 days x) 6 days y) 8 days z) 10 days

Last Answer : ANSWER: X -- 6 DAYS

. The half life period of a radioactive element depends upon the (A) Temperature (B) Pressure (C) Amount of element present (D) None of these

Description : . The half life period of a radioactive element depends upon the (A) Temperature (B) Pressure (C) Amount of element present (D) None of these

Last Answer : (D) None of these

Rubesh generally takes 80 minutes to reach home from office. Due to rain, he travelled at 2/3rd of his usual speed for the 1st half of the distance. At what speed should rubesh travel the remaining distance to reach home on time? a) 1.5 times the original speed b) 2 times the original speed c) 2.5 times the original speed d) 3 times the original speed e) Cannot reach on time

Description : Rubesh generally takes 80 minutes to reach home from office. Due to rain, he travelled at 2/3rd of his usual speed for the 1st half of the distance. At what speed should rubesh travel the remaining distance ... c) 2.5 times the original speed d) 3 times the original speed e) Cannot reach on time

Last Answer : Under the normal speed, 40 minutes for half the distance Due to rain, time taken will be 40 / (2/3) = 40 × (3/2) = 60 minutes So, in 20 minutes he has to cover the distance he usually covers in 40 minutes. So, he has to travel at twice the original speed. Answer: b)

If all of the capacity on a production line is sold a. all remaining inventory is sold for half the average cost of production. b. a loss is written off on the income statement. c. Capstone interprets the action as a liquidation instruction. d. the company will receive a cash payment of 65% the original investment on capacity. e. all of the above.

Description : If all of the capacity on a production line is sold a. all remaining inventory is sold for half the average cost of production. b. a loss is written off on the income statement. c. Capstone ... company will receive a cash payment of 65% the original investment on capacity. e. all of the above.

Last Answer : e. all of the above.

75% of a radioactive element decays in 6 hours. Its half life period is __________ hours. (A) 3/4 (B) 1/6 (C) 3 (D) 4

Description : 75% of a radioactive element decays in 6 hours. Its half life period is __________ hours. (A) 3/4 (B) 1/6 (C) 3 (D) 4

Last Answer : (C) 3

The time required for half of the __________ of a radioactive isotope to decay is called its half life. (A) Nuclei (B) Electrons

Description : The time required for half of the __________ of a radioactive isotope to decay is called its half life. (A) Nuclei (B) Electrons

Last Answer : (A) Nuclei

When a girl weighing 90 kgs left a class, the average weight of the remaining 119 students increased by 400 g. What is the average weight of the remaining 119 students? A) 124 B) 138 C) 145 D) 116

Description : When a girl weighing 90 kgs left a class, the average weight of the remaining 119 students increased by 400 g. What is the average weight of the remaining 119 students? A) 124 B) 138 C) 145 D) 116

Last Answer :  B Let the average weight of the 119 students be X. Therefore, the total weight of the 119 of them will be 119X. The questions states that when the weight of this student who left is added, the total ... , the average weight decreases by 0.4 kgs. (119X+90)/120=X−0.4 ⇒119X+90=120X−48  ⇒X=138

What is the average life of a radioactive atom having a 'half life period' of T? (A) 1.44 T (B) 0.144 T (C) 14.4 T (D) 2T

Description : What is the average life of a radioactive atom having a 'half life period' of T? (A) 1.44 T (B) 0.144 T (C) 14.4 T (D) 2T

Last Answer : (A) 1.44 T

If a radioactive sample has decayed until only one eighth of the original sample remains unchanged how many half-lives have elapsed?

Description : If a radioactive sample has decayed until only one eighth of the original sample remains unchanged how many half-lives have elapsed?

Last Answer : 3

A radioactive isotope having a half life of 3 days was received after 12 days. It was found that there were 3 gm of the isotopes in the container. The

Description : A radioactive isotope having a half life of 3 days was received after 12 days. It was found that there were 3 gm of the isotopes in the container. The

Last Answer : A radioactive isotope having a half life of 3 days was received after 12 days. It was found that there were 3 gm of ... 48 g B. 36 g C. 24 g D. 12 g

A radioactive sample has a half life 1500 years. A sealed tube conataining 1g of the sample will contain after 3000 years,

Description : A radioactive sample has a half life 1500 years. A sealed tube conataining 1g of the sample will contain after 3000 years,

Last Answer : A radioactive sample has a half life 1500 years. A sealed tube conataining 1g of the sample will contain ... g of the sample D. 0.01g of the sample

The average age of the students in a class is 14. The average age of half of the students in that class and the class teacher is 16. The average age of the remaining half of the students is 15. What is the number of students in that class? a) 20 b) 70 c) 80 d) Cannot be determined e) None of these

Description : The average age of the students in a class is 14. The average age of half of the students in that class and the class teacher is 16. The average age of the remaining half of the students is 15. What is the number of students in that class? a) 20 b) 70 c) 80 d) Cannot be determined e) None of these

Last Answer : Because total no. of students is not known we cannot find the answer. Answer: d)

Can the decay half-life of a radioactive material be changed? -Physics

Description : Can the decay half-life of a radioactive material be changed? -Physics

Last Answer : Yes, the decay half-life of a radioactive material can be changed. Radioactive decay happens when an unstable atomic nucleus spontaneously changes to a lower-energy state and spits out a bit of ... radiometric dating are so accurate because decay half-lives in nature are so close to constant.

Give reason: Radioactive material of longer half life is dangerous.

Description : Give reason: Radioactive material of longer half life is dangerous.

Last Answer : Since the radioactivity lasts longer.

For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to 1/4th of its initial volume, then the rate of reaction compared to the original rate will be __________ times. (A) 8 (B) 16 (C) 1/8 (D) 1/16

Description : For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to 1/4th of its initial volume, then the rate of reaction compared to the original rate will be __________ times. (A) 8 (B) 16 (C) 1/8 (D) 1/16

Last Answer : (B) 16

The rate of a gas phase reaction is given by K . CA . CB. If the volume of the reaction vessel is reduced to l/4th of its initial volume, then the reaction rate compared to the original rate will be __________ times. (A) 4 (B) 16 (C) 8 (D) 2

Description : The rate of a gas phase reaction is given by K . CA . CB. If the volume of the reaction vessel is reduced to l/4th of its initial volume, then the reaction rate compared to the original rate will be __________ times. (A) 4 (B) 16 (C) 8 (D) 2

Last Answer : (B) 16

A liquid decomposes by irreversible first order kinetics and the half life period of this reaction is 8 minutes. The time required for 75% conversion of the liquid will be __________ minutes. (A) 4 (B) 8 (C) 12 (D) 16

Description : A liquid decomposes by irreversible first order kinetics and the half life period of this reaction is 8 minutes. The time required for 75% conversion of the liquid will be __________ minutes. (A) 4 (B) 8 (C) 12 (D) 16

Last Answer : (D) 16

A composite flat wall of a furnace is made of two materials 'A' and 'B'. The thermal conductivity of 'A' is twice of that of material 'B', while the thickness of layer of 'A' is half that of B. If the temperature at the two sides of the wall are 400 and 1200°K, then the temperature drop (in °K) across the layer of material 'A' is (A) 125 (B) 133 (C) 150 (D) 160

Description : A composite flat wall of a furnace is made of two materials 'A' and 'B'. The thermal conductivity of 'A' is twice of that of material 'B', while the thickness of layer of 'A' is half that of B. If the temperature ... drop (in °K) across the layer of material 'A' is (A) 125 (B) 133 (C) 150 (D) 160

Last Answer : (D) 160

If a firm, or a network firm, has a direct financial interest in an audit client of the firm, the self-interest threat created would be so significant no safeguard could reduce the threat to an acceptable level. The action appropriate to permit the firm to perform the engagement would be to a. Dispose of the financial interest. b. Dispose of a sufficient amount of it so that the remaining interest is no longer material. c. Either a or b d. Neither a nor b

Description : If a firm, or a network firm, has a direct financial interest in an audit client of the firm, the self-interest threat created would be so significant no safeguard could reduce the threat to an acceptable ... that the remaining interest is no longer material. c. Either a or b d. Neither a nor b

Last Answer : Dispose of the financial interest

Radioactive decay of a material involves a __________ order reaction. (A) Third (B) Second (C) First (D) Zero

Description : Radioactive decay of a material involves a __________ order reaction. (A) Third (B) Second (C) First (D) Zero

Last Answer : (C) First

Mr. Sachin spent 20% of his monthly income on food and 15% on children’s education. 40% of the remaining he spent on entertainment and transport together and 30% on the medical. He is left with an amount of Rs.8, 775/- after all these expenditures. What is Mr. Sachin’s monthly income ?

Description : Mr. Sachin spent 20% of his monthly income on food and 15% on children's education. 40% of the remaining he spent on entertainment and transport together and 30% on the medical. He is left with an amount of Rs.8, 775/- after ... 000/- b) Rs.46,000/- c) Rs.36, 000/- d) Rs.29,000/- e) None of these

Last Answer : Let the total income of Mr.Sachin be 100 According to question, 100 – 20 –15 = 65 × 60/100 × 70/100 = 27.3. 27.3 = 100 8775 = 100/27.3 × 8775 = Rs. 32142. Answer: e)

The half-life of an isotope of an element is 5 days. The mass of a 10 gram sample of this isotope remaining after 20 days is: w) 0.312 grams x) 0.625 grams y) 1.25 grams z) 2.50 grams

Description : The half-life of an isotope of an element is 5 days. The mass of a 10 gram sample of this isotope remaining after 20 days is: w) 0.312 grams x) 0.625 grams y) 1.25 grams z) 2.50 grams

Last Answer : ANSWER: X -- 0.625 GRAMS

A reactor having a salvage value of Rs. 10000 is estimated to have a service life of 10 years. The annual interest rate is 10%. The original cost of the reactor was Rs. 80000. The book value of the reactor after 5 years using sinking fund depreciation method will be Rs. (A) 40,096 (B) 43,196 (C) 53,196 (D) 60,196

Description : A reactor having a salvage value of Rs. 10000 is estimated to have a service life of 10 years. The annual interest rate is 10%. The original cost of the reactor was Rs. 80000. The book value of the reactor after 5 years ... method will be Rs. (A) 40,096 (B) 43,196 (C) 53,196 (D) 60,196

Last Answer : D) 60,196

The half life period of a radioactive substance is best determined by counting the number of alpha particles emitted per second in a GeigerMuller counter from its known quantity. If the half life period of aradioactive substance is one month, then(A) 3/4th of it will disintegrate in two months(B) It will completely disintegrate in two months(C) It will completely disintegrate in four months(D) 1/8th of it will remain intact at the end of four months

Description : The half life period of a radioactive substance is best determined by counting the number of alpha particles emitted per second in a GeigerMuller counter from its known quantity. If the half life period of a ... in four months (D) 1/8th of it will remain intact at the end of four months

Last Answer : (B) It will completely disintegrate in two months

In a spent fuel assembly, the radioactive elements having the longest half-lives are the: w) fission products x) actinides y) activation products z) radioisotopes of lead

Description : In a spent fuel assembly, the radioactive elements having the longest half-lives are the: w) fission products x) actinides y) activation products z) radioisotopes of lead

Last Answer : ANSWER: X -- ACTINIDES

The average price of 10 books is Rs. 12 while the average price of 8 of these books is Rs. 11.75. Of the remaining two books, if the price of one book is 60% more than the price of the other, what is the price of each of these two books? A.Rs 10 and Rs 16 B.Rs 12 and Rs 24 C.Rs 24 and Rs 18 D.Rs 28 and Rs 12 E.None of these

Description : The average price of 10 books is Rs. 12 while the average price of 8 of these books is Rs. 11.75. Of the remaining two books, if the price of one book is 60% more than the price of the other, what is the price of ... and Rs 16 B.Rs 12 and Rs 24 C.Rs 24 and Rs 18 D.Rs 28 and Rs 12 E.None of these

Last Answer : Answer - A (Rs 10 and Rs 16) Explanation - Total price of the two books = Rs. [(12 x 10) - (11.75 x 8)] = Rs. (120 - 94) = Rs. 26 Let the price of one book be Rs.x Then, the price of other book = Rs. (x ... /5)x= (8/5)x so, x +(8/5)x=26 , x=10 The prices of the two books are Rs. 10 and Rs. 16

The average price of 12 note books is Rs.15 while the average price of 10 of these note books is Rs.13. Of the remaining 2 note books, if the price of one note book is 50% more than the price of the other, what is the price of each of these two note books? A) Rs. 30, Rs.20 B) Rs. 8, Rs. 30 C) Rs. 10, Rs. 16 D) Rs. 12, Rs. 20

Description : The average price of 12 note books is Rs.15 while the average price of 10 of these note books is Rs.13. Of the remaining 2 note books, if the price of one note book is 50% more than the price of the other, what is the price of ... Rs. 30, Rs.20 B) Rs. 8, Rs. 30 C) Rs. 10, Rs. 16 D) Rs. 12, Rs. 20

Last Answer : Answer: A) Total price of 12 note books = Rs. 180  Total price of 10 note books= Rs. 130 ⇒ The price of 2 note books = Rs. 50 Let the price of each book be x and y. ⇒ x + y = 50 ----- ... note book is 50% more than the other price 150y/100+y=50  y=20 Substituting y value in (1) we get, x=30

Some amount out of Rs. 10000 was lent at 6 % p.a. and the remaining at 4% p.a. If the total simple interest from both the fractions in 5 years was Rs. 1500, then the ratio of the 2 different amount is A)1:3 B)3:1 C)1:4 D)3:2

Description : Some amount out of Rs. 10000 was lent at 6 % p.a. and the remaining at 4% p.a. If the total simple interest from both the fractions in 5 years was Rs. 1500, then the ratio of the 2 different amount is A)1:3 B)3:1 C)1:4 D)3:2

Last Answer : A)1:3

Some amount out of Rs.8500 was lent at 5% per annum and the remaining was lent at 3% per annum. If the total simple interest from both the fractions in4 years was Rs.1500, the sum lent at 5% per annum was a) Rs. 2400 b) Rs. 2200 c) Rs. 2000 d) Rs. 6000

Description : Some amount out of Rs.8500 was lent at 5% per annum and the remaining was lent at 3% per annum. If the total simple interest from both the fractions in4 years was Rs.1500, the sum lent at 5% per annum was a) Rs. 2400 b) Rs. 2200 c) Rs. 2000 d) Rs. 6000

Last Answer : D Total simple interest received , I = Rs.1500 Principal , p = 8500 period, n = 4 years Rate of interest, r = ? Simple Interest, I=PNR/100 1500 = ( 8500 4 r )/ 100  = ... total amount is Rs.8500.  Therefore, the amount lent at 5% per annum (part1 amount) = 8500x12/17  = 6000 

If you start with 24 grams of a radioactive element with a half-life of one month, how many grams of the radioactive element will be left after 2 months? w) 1.5 grams x) 3 grams y) 6 grams z) 12 grams

Description : If you start with 24 grams of a radioactive element with a half-life of one month, how many grams of the radioactive element will be left after 2 months? w) 1.5 grams x) 3 grams y) 6 grams z) 12 grams

Last Answer : ANSWER: Y -- 6 GRAMS

At equilibrium the concentration of water in vapour phase (C* ) in kg/m3 of air space and the amount of water (m) adsorbed per kg of dry silica gel are related by, C* = 0.0667m. To maintain dry conditions in a room of air space 100m3 containing 2.2 kg of water vapour initially, 10 kg of dry silica gel is kept in the room. The fraction of initial water remaining in the air space after a long time (during which the temperature is maintained constant) is (A) 0.0 (B) 0.2 (C) 0.4 (D) 1.0

Description : At equilibrium the concentration of water in vapour phase (C* ) in kg/m3 of air space and the amount of water (m) adsorbed per kg of dry silica gel are related by, C* = 0.0667m. To maintain dry conditions in a room ... which the temperature is maintained constant) is (A) 0.0 (B) 0.2 (C) 0.4 (D) 1.0

Last Answer : (C) 0.4

Pick out the wrong statement. (A) Gross revenue is that total amount of capital received as a result of the sale of goods or service (B) Net revenue is the total profit remaining after deducting all costs excluding taxes (C) The ratio of immediately available cash to the total current liabilities is known as the cash ratio (D) Consolidated income statement based on a given time period indicates surplus capital and shows the relationship among total income, costs & profit over the time interval

Description : Pick out the wrong statement. (A) Gross revenue is that total amount of capital received as a result of the sale of goods or service (B) Net revenue is the total profit remaining ... indicates surplus capital and shows the relationship among total income, costs & profit over the time interval

Last Answer : (C) Working capital turnover ratio = sales/net working capital

The normal altitude of GPS satellite is about (A) 16,200 km (B) 20,200 km (C) 24,400 km (D) 36,100 km

Description : The normal altitude of GPS satellite is about (A) 16,200 km (B) 20,200 km (C) 24,400 km (D) 36,100 km

Last Answer : Answer: Option B

A decrease of 40 % in the price of coffee enables a person to buy 8 kg more for Rs 400 find the original and reduced price per kg of coffee.

Description : A decrease of 40 % in the price of coffee enables a person to buy 8 kg more for Rs 400 find the original and reduced price per kg of coffee.

Last Answer : Price of 8kg of coffee= 40% of 400 Reduced price of 8kg=160Rs Reduced price of 1kg= 20Rs Original price= 20*100/60 = Rs 33.33

Death may occur, when SO2 concentration in atmospheric air exceeds __________ ppm.(A) 20 (B) 100 (C) 400 (D) 200

Description : Death may occur, when SO2 concentration in atmospheric air exceeds __________ ppm. (A) 20 (B) 100 (C) 400 (D) 200

Last Answer : (C) 400