A Kelvin thermometer and a Fahrenheit thermometer both give the same reading for a certain sample. What would be the corresponding reading in a Celsius thermometer?

• 574

• 301

• 273

• 232

If the potential difference applied to an X-ray tube is doubled while keeping the separation between the filament and the target as same, what will happen to the cutoff wavelength?

• Will remain same

• Will be doubled

• Will be halved

• Will be four times of the original wavelength

Which one of the following statements is true for the relation $\mathrm{F}\frac{{\mathrm{Gm}}_1{\mathrm{m}}_2}{{\mathrm{r}}^2}?$

(All symbols have their usual meanings)

• The quantity G depends on the local value of g acceleration due to gravity

• The quantity G is greatest at the surface of the Earth

• The quantity G is used only when earth is one of the two masses

• The quantity G is a universal constant

If the absolute refractive indices of glass and water are 3/2 and 4/3 respectively, what will be the ratio of velocity of light in glass and water?

• 3 : 4

• 4 : 3

• 8 : 7

• 8 : 9

A positive charge +q is placed at the centre of a hollow metallic sphere of inner radius a and outer radius b. The electric field at a distance r from the centre is denoted by E. In this regard, which one of the following statements is correct?

• E = 0 for a < r < b

• E = 0 for r < a

• E = q/4πε₀r for a < r < b

• E = q/4πε₀r for r < a

Suppose the force of gravitation between two bodies of equal masses is F. If each mass is doubled keeping the distance of separation between them unchanged, the force would become

• F

• 2 F

• 4 F

• $\frac{1}{4}\mathrm{F}$

A body has a free fall from a height of 20 m. After falling through a distance of 5 m, the body would

• lose one-fourth of its total energy

• lose one-fourth of its potential energy

• gain one-fourth of its potential energy

• gain three-fourth of its total energy

Two bodies A and B are moving with equal velocities. The mass of B is double that of A. In this context, which one of the following statements is correct?

• Momentum of B will be double that of A

• Momentum of A will be double that of B

• Momentum of B will be four times that of A

• Momenta of both A and B will be equal

The S.I. unit of acceleration is

• ms^-1

• ms^-2

• cms^-2

• cms^-2

An object is placed at the centre of curvature of a concave mirror of focal length 16 cm. If the object is shifted by 8 cm towards the focus, the nature of the image would be

• real and magnified

• virtual and magnified

• real and reduced

• virtual and reduced