Heat and Temperature Obj-2 HC Verma (MCQ-2) Solutions Vol-2 Chapter-23 Concept of Physics for Class-12. Step by Step Solutions of Objective -2 (MCQ-2) Questions of Chapter-23 Heat and Temperature (Concept of Physics) .Visit official Website CISCE for detail information about ISC Board Class-11 Physics.

## Heat and Temperature Obj-2 (MCQ-2) HC Verma Solutions Vol-2 Chapter-23 Concept of Physics

 Board ISC and other board Publications Bharti Bhawan Publishers Chapter-23 Heat and Temperature Class 12 Vol 2nd writer HC Verma Book Name Concept of Physics Topics Solution of Objective-2 (MCQ-2) Questions Page-Number 12

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Heat and Temperature Obj-2 (MCQ-2) HC Verma

### HC Verma Solutions of Ch-23  Vol-II Concept of Physics for Class-12

(Page-12)

#### Question-1 :-

A spinning wheel is brought in contact with an identical wheel spinning at identical speed. The wheels slow down under the action of friction. Which of the following energies of the first wheel decreases?

(a) Kinetic
(b) Total
(c) Mechanical
(d) Internal

The options,  (a) and (c)  are correct

Explanation:

The kinetic energy of a body depends on its speed. Since when a spinning wheel is slowed down, its speed decreases leading to reduction in its kinetic energy. The mechanical energy of a body is defined as the sum of its potential and kinetic energies. Since the kinetic energy of the wheel has been decreased, it’ll lead to decrease in its mechanical energy. When the wheel slows down due to friction, its mechanical energy gets converted into heat energy, leading to increase in internal energy, which increases with increase in temperature.

#### Question-2 :-

A spinning wheel A is brought in contact with another wheel B, initially at rest. Because of the friction at contact, the second wheel also starts spinning. Which of the following energies of the wheel B increases?
(a) Kinetic
(b) Total
(c) Mechanical
(d) Internal

The all options,  (a), (b), (c) and (d) are correct

Explanation:

When the wheel B starts spinning because of the friction at contact, it will gain kinetic energy and, hence, mechanical energy (kinetic + potential energies). Also, internal energy will increase, which increases with rise in temperature. Along with it, the generation of heat energy due to friction will lead to increase in the net sum of all the energies, i.e. total energy.

#### Question-3 :-

A body A is placed on a railway platform and an identical body B in a moving train. Which of the following energies of B are greater than those of A, as seen from the ground?
(a) Kinetic
(b) Total
(c) Mechanical
(d) Internal