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21.

An ideal transformer converts 200 V  AC to 3.3 kV  AC to transmit a power of 4.4 kW .If primary coil has 600 turns, then alternating current in the secondary coil is

A) $\frac{1}{3}$ A

B) $\frac{4}{3}$ A

C) $\frac{5}{3}$ A

D) $\frac{7}{3}$ A

22.

A metal wire of density $\rho$  floats on a water surface horizontally. If it is NOT to  sink in water , then maximum radius  of wire is proportional to (where, T= surface tension of water, g= gravitational  acceleration)

A) $\sqrt{\frac{T}{\pi \rho g}}$

B) $\sqrt{\frac{\pi \rho g}{T}}$

C) $\frac{T}{\pi \rho g}$

D) $\frac{\pi \rho g}{T}$

23.

If Mz = magnetisation  of a paramagnetic sample, B- external magnetic field, T= absolute temperature, C= curie constant, then  according to Curie's law in magnetism, the correct relation is

A) $M_{z}=\frac{T}{CB}$

B) $M_{z}=\frac{CB}{T}$

C) $C=\frac{M_{z}B}{T}$

D) $C=\frac{T^{2}}{M_{Z}B}$

24.

If the numerical  aperture of a microscope is increased, then is

A) resolving power remains constant

B) resolving power becomes zero

C) limit of resolution is decreased

D) limit of resolution is increased

25.

The angle made by an incident ray of light with reflecting surface is called

A) glancing angle

B) angle of incidence

C) angle of deviation

D) angle of refraction

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