GkSeries.com

NCERT Solutions for class 11 Physics | Chapter 11 - Thermal Properties of Matter

(1) Newton’s law of cooling is applicable for
[A] small excess of temperature over the surrounding
[B] large excess of temperature over the surrounding
[C] None of these
[D] any excess of temperature over the surrounding
Answer: small excess of temperature over the surrounding
(2) 4200 J of work is required for
[A] increasing the temperature of 100 g of water through 10°C
[B] increasing the temperature of 1 kg of water through 10°C
[C] increasing the temperature of 500 g of water through 10°C
[D] increasing the temperature of 10 g of water through 10°C
Answer: increasing the temperature of 100 g of water through 10°C

DOWNLOAD CURRENT AFFAIRS PDF FROM APP

(3) Good absorbers of heat are
[A] good emitters
[B] non-emitters
[C] poor emitters
[D] highly polished
Answer: good emitters
(4) Sweet makers do not clean the bottom of cauldron because
[A] black and rough surface absorbs more heat
[B] absorption power of black and bright surface is more.
[C] transmission power of black and rough surface is more.
[D] emission power of black and bright surface is more
Answer: black and rough surface absorbs more heat
(5) Which of the following statements regarding specific heat capacity of a substance are correct ? It depends on

I. mass of substance.

II. nature of substance.

III. temperature of substance.

IV. volume of substance.

[A] II and III
[B] None of these
[C] I and II
[D] III and IV
Answer: II and III
(6) A uniform metallic rod rotates about its perpendicular bisector with constant angular speed. If it is heated uniformly to raise its temperature slightly
[A] its speed of rotation increases.
[B] its speed of rotation decreases.
[C] its speed of rotation remains same.
[D] its speed increases because its moment of inertia increases.
Answer: its speed of rotation decreases.
(7) An aluminium sphere is dipped into water. Which of the following is true?
[A] Buoyancy will be less in water at 0°C than that in water at 4°C.
[B] Buoyancy will be more in water at 0°C than that in water at 4°C.
[C] Buoyancy in water at 0°C will be same as that in water at 4°C.
[D] Buoyancy may be more or less in water at 4°C depending on the radius of the sphere.
Answer: Buoyancy will be less in water at 0°C than that in water at 4°C.
(8) A perfectly black body emits radiation at temperature T1 K. if it sis to radiate 16 times this power, its temperature T2. will be
[A] T2 = 16 T1
[B] T2 = 8 T1
[C] T1 = 4 T1
[D] T2 = 2 T1
Answer: T2 = 2 T1
(9) A black body is at 300 K. it emits energy at a rate which is proportional to
[A] (300)
[B] (300)2
[C] (300)4
[D] (300)3
Answer: (300)4
(10) The rate of radiation of black body at 0°C is E watt. The n the rate of radiation of this black body at 273°C will be
[A] 16 E
[B] 8 E
[C] 4 E
[D] E
Answer: 16 E
(11) An object is at the temperature of 400°C. at what temperature would it radiant energy twice as first? The temperature of surrounding may be assumed to be negligible
[A] 200°C
[B] 200°K
[C] 800°C
[D] 800°K
Answer: 800°K
(12) Spectrum of a perfectly black body is
[A] Line spectrum
[B] Band spectrum
[C] Continuous spectrum
[D] None of these
Answer: Continuous spectrum
(13) In which process the rate of transfer of heat is maximum?
[A] Conduction
[B] Convection
[C] Radiation
[D] In all these heat is transferred with the same velocity
Answer: Radiation
(14) A body cools from 60°C to 50°C in 10 minutes. If the room temperature is 25°C and assuming Newtonos law of cooling to hold good, the temperature of the body at the end of the next 10 minutes will be
[A] 38.5°C
[B] 40°C
[C] 42.85°C
[D] 45°C
Answer: 42.85°C
(15) The temperature of a piece of metal is raised from 27°C to 51.2°C. the rate at which metal radiates energy increases nearly
[A] 1.36 times
[B] 2.36 times
[C] 3.36 times
[D] 4.36 times
Answer: 1.36 times
(16) Three black bodies A, B and C in the form of cubes of sides in the ratio of 3: 4: 5 are kept at the same high temperature. The ratio of the quantity of heat lost per second by A, B and C will be
[A] 27: 64: 125
[B] 5:4:3
[C] 09:16:25
[D] 25:16:9
Answer: 09:16:25
(17) Two sphere of the same material have radii 1 m and 4 m and temperature 4000 K and 2000 K respectively. the energy radiated per second by the first sphere is
[A] Greater then by the second
[B] Less than that by the second
[C] Equal in both cases
[D] The information is incomplete to draw and conclusion
Answer: Equal in both cases
(18) If a = 0.72, r = 0.24, then the value of t is
[A] 0.02
[B] 0.04
[C] 0.4
[D] 0.2
Answer: 0.04
(19) A cup of tea cools from 80°C to 60°C in one minute. The ambient temperature is 30°C. in cooling from 60°C to 50°C, it will take.
[A] 50 sec
[B] 90 sec
[C] 60 sec
[D] 30 sec
Answer: 50 sec
(20) If the temperature of the sun is doubled. The rate of energy received on the earth will be increased by a factor of
[A] 2
[B] 4
[C] 8
[D] 16
Answer: 16

Please share this page

Chapters

Click Here to Read more questions

Teacher Eligibility Test