A white and smooth surface is – (1) good absorber and good reflector of heat (2) bad absorber and good reflector of heat (3) good absorber and bad reflector of heat (4) bad absorber and bad reflector of heat

A white and smooth surface is – (1) good absorber and good reflector of heat (2) bad absorber and good reflector of heat (3) good absorber and bad reflector of heat (4) bad absorber and bad reflector of heat
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(2) bad absorber and good reflector of heat Explanation: Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
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A white and smooth surface is (1) good absorber and good reflector of heat (2) bad absorber and good reflector of heat (3) good absorber and bad reflector of heat (4) bad absorber and bad reflector of heat

Description : A white and smooth surface is (1) good absorber and good reflector of heat (2) bad absorber and good reflector of heat (3) good absorber and bad reflector of heat (4) bad absorber and bad reflector of heat

Last Answer : bad absorber and good reflector of heat

The earth is a – (1) good reflector of heat (2) non-absorber of heat (3) good absorber and good radiator of heat (4) bad absorber and bad radiator of heat

Description : The earth is a – (1) good reflector of heat (2) non-absorber of heat (3) good absorber and good radiator of heat (4) bad absorber and bad radiator of heat

Last Answer : (3) good absorber and good radiator of heat Explanation: The earth's surface radiates as a black body, since it aborts and radiates with nearly 100 percent efficiency for its temperatures. Gases, on the contrary, are selective absorbers and radiators.

The earth is a (1) good reflector of heat (2) non-absorber of heat (3) good absorber and good radiator of heat (4) bad absorber and bad radiator of heat

Description : The earth is a (1) good reflector of heat (2) non-absorber of heat (3) good absorber and good radiator of heat (4) bad absorber and bad radiator of heat

Last Answer : Bad absorber and bad radaitor because all bad absorber are bad emitter. As well

Outside of cooking utensils are generally left black from below because – (1) it is difficult to clean daily. (2) black surface is a good conductor of heat. (3) black surface is a poor conductor of heat. (4) black surface is a good absorber of heat.

Description : Outside of cooking utensils are generally left black from below because – (1) it is difficult to clean daily. (2) black surface is a good conductor of heat. (3) black surface is a poor conductor of heat. (4) black surface is a good absorber of heat.

Last Answer : (4) black surface is a good absorber of heat. Explanation: The outside surface of a utensil used for heating is coated black so that it may absorb more heat and make heating quicker. This is because black surface is a good absorber of heat.

Outside of cooking utensils are generally left black from below because (1) it is difficult to clean daily. (2) black surface is a good conductor of heat. (3) black surface is a poor conductor of heat. (4) black surface is a good absorber of heat.

Description : Outside of cooking utensils are generally left black from below because (1) it is difficult to clean daily. (2) black surface is a good conductor of heat. (3) black surface is a poor conductor of heat. (4) black surface is a good absorber of heat.

Last Answer : black surface is a good absorber of heat.

A body absorbs heat most if it is – (1) black and rough (2) black and smooth (3) white and rough (4) white and smooth

Description : A body absorbs heat most if it is – (1) black and rough (2) black and smooth (3) white and rough (4) white and smooth

Last Answer : (1) black and rough Explanation: A black body is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. Another property is roughness. Sand is rough and black and so it is a good absorber.

A body absorbs heat most if it is (1) black and rough (2) black and smooth (3) white and rough (4) white and smooth

Description : A body absorbs heat most if it is (1) black and rough (2) black and smooth (3) white and rough (4) white and smooth

Last Answer : black and rough

Before X-ray examination (coloured Xray) of the stomach, patients are given suitable salt of barium because. (1) barium is a good absorber of X-rays and helps stomach to appear clearly (2) barium salts are white in colour and this helps stomach to appear clearly (3) barium allows X-rays to pass through the stomach (4) barium salts are easily available

Description : Before X-ray examination (coloured Xray) of the stomach, patients are given suitable salt of barium because. (1) barium is a good absorber of X-rays and helps stomach to appear clearly (2) barium ... clearly (3) barium allows X-rays to pass through the stomach (4) barium salts are easily available

Last Answer : (1) barium is a good absorber of X-rays and helps stomach to appear clearly

A perfect conductor acts as a a) Perfect transmitter b) Perfect reflector c) Bad transmitter d) Bad reflector

Description : A perfect conductor acts as a a) Perfect transmitter b) Perfect reflector c) Bad transmitter d) Bad reflector

Last Answer : b) Perfect reflector

A perfect dielectric acts as a a) Perfect transmitter b) Perfect reflector c) Bad transmitter d) Bad reflector

Description : A perfect dielectric acts as a a) Perfect transmitter b) Perfect reflector c) Bad transmitter d) Bad reflector

Last Answer : a) Perfect transmitter

What is the midpoint of the reflector surface of a spherical mirror called ?

Description : What is the midpoint of the reflector surface of a spherical mirror called ?

Last Answer : The center point of the reflecting surface of a spherical mirror is called pole.

What is the degree of angle between the perpendicular and the reflector ?

Description : What is the degree of angle between the perpendicular and the reflector ?

Last Answer : The angle between the perpendicular and the reflector is 90 degrees.

Who Invented the Reflector Telescope ?

Description : Who Invented the Reflector Telescope ?

Last Answer : Scientist Newton invented the reflecting telescope.

What is a reflector ?

Last Answer : The medium through which the word is reflected back is called the reflector.

Convex mirror is generally used in - (1) solar cookers (2) opthalmoscope (3) reflector for head light (4) rear view mirror

Description : Convex mirror is generally used in - (1) solar cookers (2) opthalmoscope (3) reflector for head light (4) rear view mirror

Last Answer : (4) rear view mirror Explanation: Rear view mirrors of carsare convex mirrors as they enable the driver to see a wide area of the road behind the car. The convex mirror makes the rays of ... if they were coming from its focus, thereby produdcing a diminished virtual image which the driver can see.

In an ideal case, if a point source of light is placed at the focal point in front of a concave reflector, where will the image form?

Description : In an ideal case, if a point source of light is placed at the focal point in front of a concave reflector, where will the image form?

Last Answer : ANSWER: WILL NOT FORM or FORMS AT INFINITY

A white and smooth surface is

Description : A white and smooth surface is

Last Answer : Bad absorber and good reflector of Heat.

A __________ surface has the maximum thermal emissivity out of the following. (A) Black & smooth (B) Black & rough (C) White & smooth (D) White & rough

Description : A __________ surface has the maximum thermal emissivity out of the following. (A) Black & smooth (B) Black & rough (C) White & smooth (D) White & rough

Last Answer : (B) Black & rough

Ten years old boy complains of itching. On examination, there are mucoid nodules with smooth rounded surface on the limbus, and mucous white ropy mucopurulent conjunctival discharge. He most probably suffers from: a. Trachoma b. Mucopurulent conjunctivitis c. Bulbar spring catarrh d. Purulent conjunctivitis

Description : Ten years old boy complains of itching. On examination, there are mucoid nodules with smooth rounded surface on the limbus, and mucous white ropy mucopurulent conjunctival discharge. He most ... from: a. Trachoma b. Mucopurulent conjunctivitis c. Bulbar spring catarrh d. Purulent conjunctivitis 

Last Answer : ANSWER: C 

When does the heat generated by fluid friction becomes appreciable compared to the heat transferred between the fluids? (A) At high fluid velocity (B) At low velocity (C) When fluid flows past a smooth surface (D) None of these

Description : When does the heat generated by fluid friction becomes appreciable compared to the heat transferred between the fluids? (A) At high fluid velocity (B) At low velocity (C) When fluid flows past a smooth surface (D) None of these

Last Answer : (A) At high fluid velocity

Assume a ray of light is incident on a smooth reflecting surface at an angle of incidence of 15 degrees to the normal. What is the angle between the incident ray and the reflected ray?

Description : Assume a ray of light is incident on a smooth reflecting surface at an angle of incidence of 15 degrees to the normal. What is the angle between the incident ray and the reflected ray?

Last Answer : ANSWER: 30 DEGREES

What is considered as a perfect absorber as well as a perfect emitter?  A. Gray body  B. Black body  C. Real body  D. White body

Description : What is considered as a perfect absorber as well as a perfect emitter?  A. Gray body  B. Black body  C. Real body  D. White body

Last Answer : Black body

The base of an electric iron is brightly polished mainly - (1) to make it smooth and frictionless (2) to make it rust-proof (3) to reduce heat loss by radiation (4) to make it more durable

Description : The base of an electric iron is brightly polished mainly - (1) to make it smooth and frictionless (2) to make it rust-proof (3) to reduce heat loss by radiation (4) to make it more durable

Last Answer : (3) to reduce heat loss by radiation Explanation: Polished surfaces are poor radiators of heat. So loss of heat on that account is reduced and the electric iron remains hotter than otherwise.

The base of an electric iron is brightly polished mainly - (1) to make it smooth and frictionless (2) to make it rust-proof (3) to reduce heat loss by radiation (4) to make it more durable

Description : The base of an electric iron is brightly polished mainly - (1) to make it smooth and frictionless (2) to make it rust-proof (3) to reduce heat loss by radiation (4) to make it more durable

Last Answer : (3) to reduce heat loss by radiation Explanation: Polished surfaces are poor radiators of heat. So loss of heat on that account is reduced and the electric iron remains hotter than otherwise.

An ideal coolant for a nuclear reactor should (A) Be a good absorber of neutrons (B) Be capable of attaining high temperature, only when it is pressurised (C) Have high density, but low heat transfer co-efficient (D) Be free from radiation damage and non-corrosive

Description : An ideal coolant for a nuclear reactor should (A) Be a good absorber of neutrons (B) Be capable of attaining high temperature, only when it is pressurised (C) Have high density, but low heat transfer co-efficient (D) Be free from radiation damage and non-corrosive

Last Answer : (D) Be free from radiation damage and non-corrosive

Which of the following quantities need not be fixed before starting the design of a co-current absorber? (A) Heat gain or loss (B) Flow rate of entering liquid (C) Flow rate of gas (D) None of these

Description : Which of the following quantities need not be fixed before starting the design of a co-current absorber? (A) Heat gain or loss (B) Flow rate of entering liquid (C) Flow rate of gas (D) None of these

Last Answer : (B) Flow rate of entering liquid

Absorption accompanied by heat evolution results in (A) Increased capacity of the absorber (B) Increase in equilibrium solubility (C) Decrease in equilibrium solubility (D) None of these

Description : Absorption accompanied by heat evolution results in (A) Increased capacity of the absorber (B) Increase in equilibrium solubility (C) Decrease in equilibrium solubility (D) None of these

Last Answer : (C) Decrease in equilibrium solubility

Using an organic fluid that boils at a low temperature means that energy could be regeneratedfrom waste fluids is known as ________. a) Heat exchanger b) Heat remover c) Heat pumps d) Heat absorber`

Description : Using an organic fluid that boils at a low temperature means that energy could be regeneratedfrom waste fluids is known as ________. a) Heat exchanger b) Heat remover c) Heat pumps d) Heat absorber

Last Answer : Heat pumps

When hot liquid is poured into a thick glass tumbler, it cracks because glass – (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion

Description : When hot liquid is poured into a thick glass tumbler, it cracks because glass – (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion

Last Answer : (1) is a bad conductor of heat so only inner surface expands Explanation: When hot liquid is poured into a thick glass tumbler, it cracks because glass is a bad conductor of heat so only inner surface expands.

When hot liquid is poured into a thick glass tumbler, it cracks because glass : (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion

Description : When hot liquid is poured into a thick glass tumbler, it cracks because glass : (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion

Last Answer :  is a bad conductor of heat so only inner surface expands 

To hear a clear resonance, what must be the distance between the listener and the reflector? -General Knowledge

Description : To hear a clear resonance, what must be the distance between the listener and the reflector? -General Knowledge

Last Answer : answer:

What is the minimum distance between the reflector and the source to hear the echo? ?

Description : What is the minimum distance between the reflector and the source to hear the echo? ?

Last Answer : The minimum distance between the reflector and the source to hear the echo is 18.6 meters.

What is the difference between reflex and reflector telescope ?

Description : What is the difference between reflex and reflector telescope ?

Last Answer : refractive telescope 1. This device uses two or three convex lenses or one convex lens and one concave lens to form reflection through refraction. 2. The color of the reflection in this device is ... 5. It is relatively easy to make mirrors for large children. . The scattering capacity is high.

Horn-Fed Cassegrain reflector antenna

Description : Horn-Fed Cassegrain reflector antenna

Last Answer : Design Horn-Fed Cassegrain reflector antenna for operating frequency, gain, beam width, dish ... Provide proper citations and references in write-up

To hear a clear echo, the distance between the listener and the reflector should be

Description : To hear a clear echo, the distance between the listener and the reflector should be

Last Answer : 17 METER

Which nuclear reactor uses water as a coolant, moderator and reflector ?

Description : Which nuclear reactor uses water as a coolant, moderator and reflector ?

Last Answer : Pressurised water reactor.

Which of the following improves antenna directivity? A. Driven element B. Reflector element C. Director element D. Parasitic element

Description : Which of the following improves antenna directivity? A. Driven element B. Reflector element C. Director element D. Parasitic element

Last Answer : D. Parasitic element

A dipole antenna requires to be fed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11kW. What is the gain in dB, obtained by the use if the reflector. (Gain referred to this particular dipole). A. 4.75 B. 2.6 C. 1.81 D. 4.24

Description : A dipole antenna requires to be fed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11kW ... Gain referred to this particular dipole). A. 4.75 B. 2.6 C. 1.81 D. 4.24

Last Answer : B. 2.6

The main function of a communications satellite is a/ an A. repeater B. reflector C. beacon D. observation platform

Description : The main function of a communications satellite is a/ an A. repeater B. reflector C. beacon D. observation platform

Last Answer : A. repeater

Which of the following is the basic component of a communications satellite receiver? A. On-board computer B. Reflector C. Telemetry D. Transponder

Description : Which of the following is the basic component of a communications satellite receiver? A. On-board computer B. Reflector C. Telemetry D. Transponder

Last Answer : D. Transponder

Known as the technique for adding a series inductor at or near the center of an antenna element in order to cancel the capacitive reactance of an antenna. A. Dipole B. Center loading C. Reflector D. loading coil

Description : Known as the technique for adding a series inductor at or near the center of an antenna element in order to cancel the capacitive reactance of an antenna. A. Dipole B. Center loading C. Reflector D. loading coil

Last Answer : D. loading coil

The reflector and director of an antenna array are considered as A. Parasitic elements B. Transcendental elements C. Feed-points D. Driven elements

Description : The reflector and director of an antenna array are considered as A. Parasitic elements B. Transcendental elements C. Feed-points D. Driven elements

Last Answer : A. Parasitic elements

A dipole antenna requires to be feed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11 kW. What is the gain in dB obtain by the use of the reflector ? ( Gain referred to this particular dipole) A. 4.24 B. 1.81 C. 4.75 D. 2.6

Description : A dipole antenna requires to be feed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11 ... ( Gain referred to this particular dipole) A. 4.24 B. 1.81 C. 4.75 D. 2.6

Last Answer : D. 2.6

A type of array antenna which consists of one half-wave driven dipole, one reflector and one director A. Hertzian dipole B. Yagi-uda C. Broadside collinear D. Log periodic dipole array

Description : A type of array antenna which consists of one half-wave driven dipole, one reflector and one director A. Hertzian dipole B. Yagi-uda C. Broadside collinear D. Log periodic dipole array

Last Answer : B. Yagi-uda

ECE Board Exam March 1996 An antenna that is circularly polarized is the ____________. A. parabolic reflector B. helical C. Yagi-uda D. small circular loop

Description : ECE Board Exam March 1996 An antenna that is circularly polarized is the ____________. A. parabolic reflector B. helical C. Yagi-uda D. small circular loop

Last Answer : B. helical

A concave mirror cannot be used as : (a) a magnifying mirror (b) a torch reflector (c) a dentist‘s mirror (d) a rear view mirror

Description : A concave mirror cannot be used as : (a) a magnifying mirror (b) a torch reflector (c) a dentist‘s mirror (d) a rear view mirror

Last Answer : (c) a dentist‘s mirror

The broadside array consists of a flat reflector and what other elements?

Description : The broadside array consists of a flat reflector and what other elements?

Last Answer : Two or more half-wave dipoles.

How many major lobes are produced by a paraboloid reflector?

Description : How many major lobes are produced by a paraboloid reflector?

Last Answer : One.

A parabolic reflector changes a spherical wavefront to what type of wavefront?

Description : A parabolic reflector changes a spherical wavefront to what type of wavefront?

Last Answer : Plane.

How many major lobes are radiated by a parabolic reflector?

Description : How many major lobes are radiated by a parabolic reflector?

Last Answer : One