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 ?
20 A
100 A
2 A
B.
20 A
We know that,
Power in the secondary coil = Power in the pnmary coil
(voltage aacross secondary coil = VS)
(voltage across primary coil = VP)
(NP = Number of turns in primary coil)]
(NS = Number of turns in secondary coil)
where NS = 50 turn, NP = 1000 turn
VP = 220 V, VS = ?
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
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
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
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 = .
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