Navbodh Physics Class 12

5/5 - (17 votes)

Navbodh Physics Class 12. We covered all the Navbodh Physics Class 12 in this post for free so that you can practice well for the exam.

Select your language and change this post to your favorite language.

Install our MCQTUBE Android app from the Google Play Store and prepare for any competitive government exams for free.

Join Telegram Group and Get FREE Alerts! Join Now

Join WhatsApp Group For FREE Alerts! Join Now

These types of competitive MCQs appear in exams like MHT-CET, NEET, JEE (Mains), and other Competitive Examinations, etc.

We also provided the Navbodh Physics class 12th book pdf download in English and Hindi medium file on our website for your convenience.

You will get their respective links in the related posts section provided below.

Related Posts:

Questions hide

Navbodh Physics Class 12 Mock Test for Students

A cube of metal is given a positive charge Q. For this system, which of the following statements is true?

(A) The electric field is normal to the surface of the cube

(B) The electric field varies within the cube

(C) Electric potential within the cube is zero

(D) Electric potential at the surface of the cube is zero

Option a - The electric field is normal to the surface of the cube

If a +vely charged body is connected to the earth, its potential becomes :

(A) zero

(B) positive

(C) infinity

(D) negative

Option a - zero

A hollow metal sphere of radius 5 cm is charged such that the potential on its surface is 50V. The potential at the center of the sphere is :

(A) 50 V

(B) zero

(C) same as at a point 5 cm away from the surface

(D) same as at a point 10 cm away from the surface

Option a - 50 V

The potential gradient is a :

(A) vector quantity

(B) scalar quantity

(C) conversion factor

(D) constant

Option a - vector quantity

An equipotential surface is that surface on which each and every point has :

(A) zero potential

(B) same potential

(C) negative potential

(D) different potential

Option b - same potential

Two copper spheres of the same radii one hollow and the other solid are charged to the same potential which will hold more charge?

(A) Solid sphere

(B) Hollow sphere

(C) Both will hold an equal charge

(D) Nothing can be predicted

Option c - Both will hold an equal charge

Two spheres of different radii are connected with the help of a metallic wire. A charge is given to the bigger sphere then :

(A) the larger sphere will have less potential

(B) the larger sphere will have more potential

(C) both will have the same potential

(D) the smaller sphere will have zero potential

Option c - both will have the same potential

The work done in an electric field in taking unit positive charge once around a charge +q (stationary) along a circle of radius r is :

(A) positive

(B) zero

(C) negative

(D) infinite

Option b - zero

The temperature of the black body becomes half of its original temperature. The amount of radiation emitted by the body will reduce to

(A) 1/2

(B) 1/16

(C) 1/4

(D) 1/8

Option b - 1/16

A body at 227 °C radiates heat at the rate of 5 cal/s cm². The rate of heat radiated in cal/s cm² at 727 °C is :

(A) 40

(B) 80

(C) 160

(D) 240

Option b - 80

The ratio of the rate of radiation of heat of the body at 227 °C to that of the same body at 27 °C is :

(A) 25 : 9

(B) 125 : 27

(C) 5 : 3

(D) 625 : 81

Option d - 625 : 81

The ratio of the rate of emission of heat by a perfectly black body at 427 °C and at 127 °C is :

(A) 7 : 4

(B) 343 : 64

(C) 49:16

(D) 2401 : 256

Option d - 2401 : 256

Two spherical bodies of the same material having radii in the ratio 2 : 1, therefore the rate of radiation of heat by them at a given temperature is in the ratio of :

(A) 1 : 2

(B) 2 : 1

(C) 4 : 1

(D) 1 : 4

Option c - 4 : 1

The rate of radiation from a black body at 0 °C is E J/s. Then the rate of radiation from this black body at 273 °C will be :

(A) 16 E

(B) 8 E

(C) 4 E

(D) E

Option a - 16 E

An electric heater, assumed to be a black body, has a temperature of 727 °C. If its temperature is raised to 1727 °C, the amount of energy radiated per unit of time now as compared with that in the first case will be :

(A) 2 times

(B) 4 times

(C) 16 times

(D) 100 times

Option c - 16 times

A black body radiates energy at the rate of E W/m² at a high-temperature T K. When the temperature is reduced to T/2 K, the radiant energy will be :

(A) E/16

(B) E/4

(C) 4E

(D) 16E

Option a - E/16

Two spheres P and Q of the same color, having radii 8 cm and 2 cm respectively, are maintained at temperatures of 127 °C and 527 °C, respectively. The ratio of the energy radiated per second by P and Q is :

(A) 0.054

(B) 0.0034

(C) 1

(D) 2

Option c - 1

An object is at a temperature of 400 °C. At what temperature would it radiate energy twice as first? (The temperature of the surroundings may be assumed to be negligible) :

(A) 200 °C

(B) 200 K

(C) 800 °C

(D) 800 K

Option d - 800 K

The radiant energy from the sun incident normally at the surface of the earth is 20 kcal/min m². What would have been the radiant energy incident normally on the earth, if the sun had a temperature twice the present one?

(A) 40 kcal/min m²

(B) 80 kcal/min m²

(C) 160 kcal/min m²

(D) 320 kcal/min m²

Option d - 320 kcal/min m²

The temperature of a piece of metal is raised from 27 °C to 51.2 °C. The rate at which the metal radiates energy increases nearly :

(A) 2 times

(B) 4 times

(C) 4.46 times

(D) 1.36 times

Option d - 1.36 times

If the temperature of the sun is doubled, the rate of energy received on Earth will be increased by a factor of

(A) 2

(B) 4

(C) 8

(D) 16

Option d - 16

A body radiates 5 W energy at a temperature of 400 K. If the temperature is increased to 1200 K, then it will radiate energy :

(A) 81 W

(B) 200 W

(C) 405 W

(D) 410 W

Option c - 405 W

Radiation emitted by a surface is directly proportional to

(A) the Third power of its absolute temperature

(B) Equal to its absolute temperature

(C) Twice the power of its absolute temperature

(D) the Fourth power of its absolute temperature

Option d - the Fourth power of its absolute temperature

If the temperature of a perfectly black body increased two times, then the rate of radiation of a perfectly black body increases by :

Join Telegram Group and Get FREE Alerts! Join Now

Join WhatsApp Group For FREE Alerts! Join Now

(A) Two times

(B) Four times

(C) Eight times

(D) Sixteen times

Option d - Sixteen times

The rate of emission of radiant energy per unit area of a body per unit of time is proportional to the fourth power of its absolute temperature. This law is known as

(A) Lein's law

(B) Wein's displacement law

(C) Stefan's law

(D) Newton's law of cooling

Option c - Stefan's law

Which of the following statement is WRONG?:

(A) Stefan's constant is the same for all black bodies.

(B) Thermal radiations travel with the speed of 3 × 108 m/s

(C) Thermal radiations exhibit diffraction

(D) Stefan's law is applicable to all heated bodies

Option d - Stefan's law is applicable to all heated bodies

A metal cube of each side 0.05 m long emits 0.6 kcal in 80 seconds. Then the emissive power of its surface in kcal/s m² 2 is :

(A) 0.5

(B) 0.05

(C) 5

(D) 5 x 10²

Option a - 0.5

The emissive power of a sphere of area of 0.02 m² is 0.5 kcal/sm². What is the amount of heat radiated by the spherical surface in 20 seconds?:

(A) 0.2 kcal

(B) 2 kcal

(C) 0.02 kcal

(D) 0.002 kcal

Option a - 0.2 kcal

The emissive power of a body is :

(A) The energy emitted by the body at a given temperature

(B) The energy emitted per unit of time by the body at a given temperature

(C) The energy emitted per unit of time per unit of surface area by the body at a given temperature

(D) Ratio of the energy emitted to the energy absorbed by the body at a given temperature

Option c - The energy emitted per unit of time per unit of surface area by the body at a given temperature

512 calories of radiant heat are incident on a body which absorbs 224 calories. What is its coefficient of emission? :

(A) 0.7

(B) 0.4375

(C) 0.8

(D) 0.6

Option b - 0.4375

A black body emits :

(A) Radiation of all wavelengths

(B) No radiation

(C) Radiations of only one wavelength

(D) Radiations of selected wavelengths

Option a - Radiation of all wavelengths

A body that absorbs all the radiations incident on it is called a :

(A) Black body

(B) Perfectly black body

(C) Good absorber

(D) Good emitter

Option b - Perfectly black body

A perfectly black body is one whose coefficient of emission is :

(A) Minimum

(B) Maximum

(C) Unity

(D) Zero

Option c - Unity

SI unit of emissive power is :

(A) J/s

(B) J/m²

(C) J/s m²

(D) W/m

Option c - J/s m²

The substances through which heat radiations can not pass are called as

(A) Good absorbers

(B) Good transmitters

(C) Diathermanous

(D) Athermanous

Option d - Athermanous

For athermanous substances, the coefficient of transmission is :

(A) Zero

(B) Greater than one

(C) Equal to one

(D) Less than one

Option a - Zero

The coefficient of reflection of the perfect black body is :

(A) Zero

(B) Unity

(C) Infinity

(D) 0.4

Option a - Zero

If the incident energy is 200 cal, absorptive power is 0.31, and reflection coefficient is 0.41, then the amount of energy transmitted will be :

(A) 48 cal

(B) 58 cal

(C) 56 cal

(D) 54 cal

Option c - 56 cal

If an athermanous body absorbs 30% of the incident radiant energy, then the reflection coefficient of the body is :

(A) 0.3

(B) Zero

(C) 0.7

(D) 1

Option c - 0.7

Out of 10 J of radiant energy incident on a surface, the energy absorbed by the surface is 2 J and the energy reflected is 6 J. Then the coefficient of transmission of the body is :

(A) 0.2

(B) 0.6

(C) 0.1

(D) Zero

Option a - 0.2

The coefficient of absorption of the surface of a body is 0.68. When 100 calories of heat are incident on the body, 27 calories are reflected from the surface. Then the coefficient of transmission of the body is :

(A) 0.95

(B) 0.5

(C) 0.05

(D) 0.27

Option c - 0.05

An athermanous metal plate has a coefficient of absorption of 0.65. Its coefficient of reflection is :

(A) 0

(B) 0.35

(C) 0.65

(D) 0.45

Option b - 0.35

Heat is incident at the rate of 10 W on an opaque emissivity of 0.8. Find the quantity of body having heat reflected by it in 1 minute: radiant

(A) 2 J

(B) 120 J

(C) 8 J

(D) 12 J

Option b - 120 J

The substances through which heat radiations can pass are called as

(A) Conductors

(B) Absorbers

(C) Diathermanous

(D) Athermanous

Option c - Diathermanous

Electromagnetic radiation is emitted :

(A) Only by radio and T. V. transmitting antennas

(B) Only by bodies at temperatures higher than their surroundings

(C) Only by red-hot bodies

(D) By all bodies

Option d - By all bodies

Heat is transmitted from higher to lower temperatures through molecular collision in

(A) Conduction

(B) Convection

(C) Radiation

(D) Combustion

Option a - Conduction

For conduction of heat, the medium should be such that :

(A) On increasing the temperature the molecule should not vibrate and it should not move

(B) Molecules can move in the whole of the medium

(C) Molecules can vibrate about their positions on increasing the temperature

(D) There is no need for a medium

Option c - Molecules can vibrate about their positions on increasing the temperature

Heat radiation belongs to ( Navbodh physics class 12 )

(A) Ultraviolet spectrum

(B) Visible spectrum

(C) Infrared spectrum

(D) Radio wave spectrum

Option c - Infrared spectrum

In the case of a body, the ratio Р of the amount of energy absorbed to the amount of energy incident on it is known as its :

(A) Absorptive power

(B) Emissive power

(C) Radiating power

(D) Transmissive power

Option a - Absorptive power

A calorimeter full of hot water is hung in a vacuum. It will :

(A) Cool by conduction

(B) Cool by radiation

(C) Cool by convection

(D) Not cool at all

Option b - Cool by radiation

Two bodies one hot and the other cold are kept in a vacuum. What will happen to the temperature of the hot body after some time? :

(A) Remains the same

(B) Increases due to radiation

(C) Decreases due to radiation

(D) Increases due to convection

Option c - Decreases due to radiation

Ventilators are provided at the top of the room : ( Navbodh physics class 12 )

(A) To bring oxygen for breathing

(B) So that sunlight may enter the room

(C) To maintain convection currents to keep the air fresh in the room

(D) To provide an outlet for carbon dioxide

Option c - To maintain convection currents to keep the air fresh in the room

A man would feel iron or wooden balls equally hot or cold at

(A) 98.4 °C

(B) 98.4 K

(C) 98.4 °R

(D) 98.4 °F

Option d - 98.4 °F

If a liquid is heated in space under no gravity, the transfer of heat will take place through a process of

(A) Conduction

(B) Convection

(C) Radiation

(D) Cannot be heated in the absence of gravity

Option a - Conduction

The velocity of heat radiation in a vacuum is :

(A) Equal to that of light

(B) Less than that of light

(C) Greater than that of light

(D) Equal to that of sound

Option a - Equal to that of light

For which of the following process, thermal conduction is maximum?

(A) Conduction

(B) Convection

(C) Radiation

(D) Combustion

Option c - Radiation

Water is usually heated by :

(A) Conduction

(B) Convection

(C) Radiation

(D) Combustion

Option b - Convection

Metals are good conductors of heat because ( Navbodh physics class 12 )

(A) These contain a large number of free electrons

(B) Their atoms are relatively far apart

(C) Their atoms collide frequently

(D) They have reflecting surfaces

Option a - These contain a large number of free electrons

In natural convection a heated portion of a liquid moves because

(A) Its molecular motion becomes aligned

(B) Of molecular collisions within it

(C) Its density is less than that of the surrounding fluid

(D) Of currents of the surrounding fluid

Option c - Its density is less than that of the surrounding fluid

We covered all the navbodh physics class 12 above in this post for free so that you can practice well for the exam.

Check out the latest MCQ content by visiting our mcqtube website homepage.

Also, check out:

Join Telegram Group and Get FREE Alerts! Join Now

Join WhatsApp Group For FREE Alerts! Join Now

Hello, I am the admin of mcqtube.com website. I am a blogger and app developer. Thanks.

Leave a Comment

Sticky Bottom Popup