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
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
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
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
Description : Assertion (A) : Half life of a radioactive isotope is the time required to decrease its mass number by half Reason (R ) : Half life of radioactive iso
Last Answer : Assertion (A) : Half life of a radioactive isotope is the time required to decrease its mass number by half ... . If both (A) and (R ) are incorrect.
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?
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
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
Description : 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
Last Answer : (D) 1/16
Description : What name is given to the time taken for half the atoms in a sample of a radioactive isotope to decay?
Last Answer : Half-life
Description : At a fuel check you have 60 US gallons (USG) of usable fuel remaining. Alternative fuel required is 12USG. The flight time remaining is 1 hour 35 mins. What is the highest consumption rate acceptable? a. 33.0 USG/Hr b. 37.9 USG/Hr c. 30.3 USG/Hr d. 21.3 USG/Hr
Last Answer : c. 30.3 USG/Hr
Description : What type of decay involves only the release of high-energy photons and therefore does not change the mass of an atom of a radioactive isotope?
Last Answer : High-energy photons are gamma rays; the decay is called gamma decay. Please note that the mass of an atom DOES change, since a loss of energy is accompanied by a loss in mass.
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
Description : Excluding the stoppages, the speed of a bus is 64 km/hr and including the stoppages the speed of the bus is 48km/hr. For how many minutes does the bus stop per hour? 1) 15 min 2) 10 min 3) 12 min 4) 20 min 5) 18 min
Last Answer : 1) 15 min
Description : (A) The archaeological studies are based on the radioactive decay of carbon-14 isotope. (R ) The ratio of C-14 to C-12 in the animals of plants is the
Last Answer : (A) The archaeological studies are based on the radioactive decay of carbon-14 isotope. (R ) The ratio of C ... D. If both (A) and (R ) are incorrect.
Description : Tharun has to cover a distance of 84 km in 40 minutes. If he covers one-half of the distance in one-fourth of the total time, to cover the remaining distance in the remaining time, what should be his speed in km/hr? a) 42 km/hr b) 64km/hr c) 84km/hr d)76km/hr
Last Answer : C Tharun needs to cover 84 km in 40minutes Given that he covers one-half of the distance in one-fourth of the total time ⇒ he covers half of 84km in one-fourth of 40 minutes ⇒ He covers 42 km in ¼ * ... Distance =42km Time =30minutes =1/2 hr Required Speed = Distance / Time =42/(1/2)=84 km/hr
Description : A radioactive element gets spilled over the floor of a room. Its half life period is 30 days. If its initial activity is ten times the permissible val
Last Answer : A radioactive element gets spilled over the floor of a room. Its half life period is 30 days. If its initial ... B. 1000 days C. 300 days D. 10 days
Description : Fifty micrograms of an isotope have decayed to 12.5 micrograms after 12 hours. What is the half life of the radioisotope?
Last Answer : ANSWER: SIX HOURS
Description : A bike starts with a speed of 60 km/hr at 8a.m. Due to the problem in engine it reduces its speed as 20 km/hr for every 1 hour. After 9 am, the time taken to covers 15 km is: a) 13 minutes and 20 seconds b) 15 minutes and 09 seconds c) 18 minutes and 15 seconds d) 22 minutes and 30 seconds
Last Answer : 15 min
Description : What is the half-life of carbon 12 isotope ?
Last Answer : Carbon -12 is a normal atom. It is not radioactive. C- 14 is radioactive. Its half -life is 5,630 years
Description : A sample of radioactive material has mass `m`, decay constant `lambda`, and molecular weight `M`. Avogadro constant `=N_(A)`. The initial activity of
Last Answer : A sample of radioactive material has mass `m`, decay constant `lambda`, and molecular weight `M`. Avogadro constant ... N_(4))/(M)` D. `mMe^(lambda)`
Description : Is the decay of a radioactive isotope predictable (causally determined) or not?
Last Answer : At this point it seems to be a result of quantum indeterminacy. In other words, since the Heisenberg uncertainty principle is in effect at that level, all we can determine is probability (hence a predictable ... , it is deterministic and we will (hopefully) one day be able to understand it as such.
Description : The radioactive isotope of cerium - 137 of weigh 8g was collected on 1st Feb. 2006 kept in a sealed tube. On 1st July, 2006, it was found that only 0.
Last Answer : The radioactive isotope of cerium - 137 of weigh 8g was collected on 1st Feb. 2006 kept in a sealed tube. On ... days B. 30 days C. 25 days D. 50 days
Description : Which radioactive isotope is used to detect tumours?
Last Answer : Which radioactive isotope is used to detect tumours? A. `.^(74)As` B. `.^(24)Na` C. `.^(131)I` D. `.^(60)Co`
Description : When `._(13)^(27)Al` is bombarded whith `alpha`-particles, a radioactive isotope of phosphorus `._(15)^(30)P` with the emission of …. Is formed
Last Answer : When `._(13)^(27)Al` is bombarded whith `alpha`-particles, a radioactive isotope of phosphorus ` ... A. neutrons B. protons C. positrons D. electrons
Description : When an isotope is blank it is radioactive?
Last Answer : When an isotope is unstable, it is said to be radioactive.
Description : When does an isotope undergo radioactive decay?
Last Answer : An atom of a given isotope will undergo radioactive decay whenever it feels like it. No joke. The nucleus of a radioactive isotope is unstable. Always. But that atom has no predictable moment ... to decay, except that those with very short half lives will pretty much disappear relatively quickly.
Description : A radioactive isotope labeled cDNA probe is used in (A) Southern blotting (B) Northern blotting (C) Both (A) and (B) (D) None of these
Last Answer : Answer : C
Description : Which one is the radioactive isotope of hydrogen? (A) Deuterium (B) Ortho-hydrogen (C) Tritium (D) None of these
Last Answer : (C) Tritium
Description : A radioactive isotope undergoes decay with respect to time following __________ law. (A) Logarithmic (B) Exponential (C) Linear (D) Inverse square
Last Answer : (B) Exponential
Description : The radioactive isotope of hydrogen is called--------- and its nucleus contains --------proton and --- --neutron.
Last Answer : Ans: Tritium, one and two
Description : Radioactive isotope of Uranium used in Nuclear Bomb is ? A.92 U 235 (Answer) B.92 U 234 C. 92 U 233 D. 92 U 238
Last Answer : A.92 U 235 (Answer)
Description : Which technique has helped in investigation of Calvin cycle? (a) X-ray crystallography (b) X-ray technique (c) Radioactive isotope technique (d) Intermittent light
Last Answer : (c) Radioactive isotope technique
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
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
Description : 3 faucet P,Q & R can fill a cistern in 12 hrs. After working together for 4hrs, R is closed P and Q can fill the remaining part in 14 hrs. The number of hrs taken by R alone to fill the cistern is. A) 18 hrs B) 20 hrs C) 28hrs D) 30hrs
Last Answer : C Part filled in 4 hrs = 4/12 = 1/3 Remaining part = 2/3 (P+Q)’s 14 hrs work = 2/3 (P+Q)’s 1 hr work = 2/ 3 *14 = 1/21 R’s 1 hr work = (P+Q+R)’s 1 hr work – (P+Q)’s 1 hr work = 1/12 – 1/21 = 7-4/84 = 3/84 = 1/28 R alone can fill the tank in 28 hrs.
Description : Three taps P,Q,R can fill a bunker in 3 hrs. After working at it together for 1 hr, R is closed and P,Q can fill the remaining part in 3 hrs. The number of hrs taken by R alone to fill the bunker. A) 9hrs B) 7hrs C) 11hrs D) 5hrs
Last Answer : A Part filled in 1 hr = 1/3 Remaining part = 1 – 1/3 = 2/3 (P + Q)’s 3 hours work = 2/3 (P+Q)’s 1 hour work = 2/9 R’s 1 hr work = [(P+Q+R)’s 1 hr work – (P+Q)’s 1 hr work] = 1/3 – 2/9 = 3-2/9 = 1/9 R alone can fill the tank in 9 hours.
Description : At a fuel check you have 60 US gallons (USG) of useable fuel remaining. Alternative fuel required is 12 USG. The flight time remaining is 1 hour 35 mins. What is the highest consumption rate acceptable?
Last Answer : 30.3 USG/HR
Description : The half - life of a radioactive substance depends upon (a) Its temperature (b) The external pressure (c) The mass of the substance (d) The strength of the nuclear force between the nucleons its atoms
Last Answer : Ans:(d)
Description : Which of the following is the same for both radioactive iodine and stable iodine? w) number of neutrons x) mass number y) half-life z) chemical properties
Last Answer : ANSWER: Z -- CHEMICAL PROPERTIES
Description : What fraction of an original sample of a radio isotope remains after 3 half-life periods?
Last Answer : One eighth remains.
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)
Description : How old is a bottle of wine if the tritium activity is 25 counts/hr and new wine has an activity 200 counts/hr The half life if tritium is 12.3 years.?
Last Answer : I don’t understand the question
Description : It is required to maintain a therapeutic concentration of 10 microgram/mL for 12 hours of a drug having half life of 1.386 hr and Vd of 5 L. The dose required in a sustained release product will be (A) 600 mg (B) 300 mg (C) 30 mg (D) 60 mg
Last Answer : (B) 300 mg
Description : A this usual rowing rate, Mohit can travel 12 miles downstream in a certain river in 6 hours less than it takes him to travel the same distance upstream. But if he could double his usual rowing rate for his 24 miles round trip, ... current in miles per hour? A.2.5m/hr B.4 m/hr C.8/3 m/hr D. 5/3m/hr
Last Answer : Answer-C Basic Formula: Speed of the stream = ½ (a-b) km/hr Explanation: Let the speed in still water be x m/hr Speed of stream be y m/hr Then, speed upstream = x-y m/hr and Speed downstream = x+y m/hr 12/x-y - ... 1] 3y^2 = 8 y so, y = 8/3 speed of the current = 8/3 m/hr = 2 (2/3) m/hr
Description : Raghu starts a bike at 40 km/hr and he increases his speed in every hour by 4 km/hr. Then the maximum distance covered by him in 12 hours is: a) 744 km b) 658 km c) 436 km d) 512 km
Last Answer : A Speed of the rider = 40km/hr. Distance covered in 1st hour = 40 km. He increased his speed in every 1 hour by 4 km/hr. Distance covered in every 1 hours will be, 44, 48, ,... upto 12 terms.(for 12 hours). ... (2(40)+(11)4) = 6(80 + 44) = 6(124) = 744. Hence, he covers 744 km in 12 hours.
Description : A train 200m in length, travels at 120 km/hr. In what time it will pass a boy who is walking at 12km an hour. a) against(opposite) it: b) in the same direction? A) 5.4,6.66 B) 7.2,5.2 C) 3.5,6 D) 12,16
Last Answer : ANSWER: A Explanation: I) Speed of the train = 120 km/hr Speed of the boy = 12 km/hr Relative speed = (120 + 12) km/hr Convert km/hr into m/s 132 km/hr = (132 * 5/ 18)m/s = 36.66 m/s Time = ... km/hr = (108 * 5 / 18)m/s = 30 sec Time = distance / speed = 200 / 30 = 6.66 sec
Description : Hemant sold 10 sarees for a total profit of Rs. 460 and 12 sarees for a total profit of Rs. 144. At what profit per saree should he sell the remaining 20 sarees so that he gets an average profit of Rs. 18 per sarees? A. Rs 7.10 B. Rs 7.60 C. Rs 7.99 D. Rs 8
Last Answer : Answer – B (Rs 7.60) Explanation – Total profit required = Rs.(42 x 18) = Rs.756 Profit on 22 sarees = Rs. (460 + 144) = Rs. 604 Profit on 20 sarees = Rs. (756 – 604) = Rs. 152 Average profit on these sarees = Rs.(152/20) = Rs. 7.60