31. The amount of energy required to change a kilogram of ice block into water without a change in temperature is?

- A. specific latent heat of fusion of ice
- B. specific heat capacity of rice
- C. heat capacity of rice
- D. specific heat of vaporization of rice

**Correct Option: Answer is A**

**32. Which expression gives magnetic flux? **

**Correct Option: Answer is C**

the magnetic flux through a surface is the surface integral of the normal component of the magnetic field B over that surface.

It is usually denoted Φ or ΦB. The SI unit of magnetic flux is the weber

Mathematically it is represented as **B = Φ/A**

where B is magnetic flux density in teslas (T),

Φ is magnetic flux in webers (Wb), and

A is area in square meters (m2).

**33. **The graph of pressure (P) against the reciprocal of the volume (I/V) in Boyles’s law is a?

- A. hyperbola
- B. parabola
- C. curve
- D. straight line

**Correct Option: Answer is A**

The pressure (p) of a given quantity of gas varies inversely with its volume (v) at constant temperature; i.e., in equation form, pv = k, a constant.

The graph of Boyle’s law is called the PV curve.

This graph of Boyle’s law is not straight but hyperbolic; this is because the statement says that at a constant temperature the pressure and the volume are inversely proportional.

**34. **What quantity of heat is required to convert 20 g of ice at 0 ºC to water at the same temperature? (Specific latent heat of ice = 336 Jg^{−1})

- A. 7.06 x 10
^{3}J - B. 5.38 x 10
^{3}J - C. 6.72 x 10
^{3}J - D. 1.35 x 10
^{3}J

**Correct Option: Answer is C**

**35. **A train of mass 1600 kg attains a speed of 25 ms^{−1} in 20 seconds. The power developed in the engine is?

- A. 2.5 KW
- B. 80 KW
- C. 25 KW
- D. 50 KW

**Correct Option: Answer is D**

**36. **The main factor which affects the speed of sound wave is the?

- A. properties of the medium
- B. amplitude of the sound wave
- C. intensity of the sound wave
- D. loudness of the sound wave

**Correct Option: Answer is A**

**37. **A semiconductor is formed by?

- A. co-ordinate bonds
- B. electrovalent bonds
- C. a substance free of bonds
- D. covalent bonds

**Correct Option: Answer is D**

It’s generally created using silicon, germanium, or other pure elements.

Semiconductors are created by adding impurities to the element.

**38. **One of the following is a scalar quantity?

- A. weight
- B. momentum
- C. potential energy
- D. moments

**Correct Option: Answer is C**

**39. **The mercury column in the barometer at notational atmospheric pressure has a height of?

- A. 0.76 cm at see level
- B. 760 cm at sea level
- C. 7.6 cm at sea level
- D. 76 cm at sea level

**Correct Option: Answer is D**

**40. **If an object just begins to slide on a surface inclined at 30º to the horizontal, the coefficient of friction is?

- A. √3
- B. √3/2
- C. 1/√2
- D. 1/√3

**Correct Option: Answer is D**

A body sliding down a plane inclined at 30o to the horizontal,

Has coefficient of friction = tan 30º or 1√3