A step down transformer has 50 turns on secondary and 1000 turns on primary winding. If a transformer is connected to 220 V, 1 A AC source, what is output current of the transformer ?

• $\frac{1}{20} \mathrm{A}$

• 20 A

• 100 A

• 2 A

The average power dissipated in AC circuit is 2 W. If a current flowing through a circuit is 2 A impedance is 1 Ω, what is the power factor of the AC circuit ?

• 0.5

• 1

• Zero

• $\frac{1}{\sqrt{2}}$

A plane electromagnetic wave of frequency 20 MHz travels through a space along x-direction. If the electric field vector at a certain point in space is 6 Vm^-1, what is the magnetic field vector at that point ?

• 2 × 10^-3 T

• 2 × 10^-8 T

• 2 T

• $\frac{1}{2} \mathrm{T}$

Two capacitors of 10 pF and 20 pF are connected to 200 V and 100 V sources respectively. If they are connected by the wire, what is the common potential of the capacitors ?

• 133.3 V

• 150 V

• 300 V

• 400 V

An object is placed at 20 cm in front of a concave mirror produces three times magnified real image. What is the focal length of the concave mirror ?

• 15 cm

• 6.6 cm

• 10 cm

• 7.5 cm

46.

A focal length of a lens is 10 cm. What is power of a lens in dioptre ?

• 0.1 D

• 10 D

• 15 D

• 1 D

A microscope is having objective of focal length 1 cm and eyepiece of focal length 6 cm. If tube length is 30 cm and image is formed at the least distance of distinct vision, what is the magnification produced by the microscope. Take D = 25cm.

• 6

• 150

• 25

• 125

A fringe width of a certain interference pattern is β = 0.002 cm. What is the distance of 5th dark fringe from centre ?

• 1 × 10^-2 cm

• 11 × 10^-2 cm

• 9 × 10^-3 cm

• 3.28 × 10⁶ cm

Diameter of the objective of a telescope is 200 cm. What is the resolving power of a telescope ? Take wavelength of light = $5000 \stackrel{\circ }{\mathrm{A}}$.

• 6.56 × 10⁶

• 3.28 × 10⁵

• 1 × 10⁶

• 3.28 × 10⁶

A polarized light of intensity I₀ is passed through another polarizer whose pass axis makes an angle of 60° with the pass axis of the former. What is the intensity of emergent polarized light from second polarizer ?

• I = I₀

• I = I₀/6

• I = I₀/5

• I₀/4