Physics

1. Which wavelength of sun is used finally as electric energy?

Visible light

Micro waves

Radio waves

Infra red waves

Question 1 of 15

2. Flash light equipped with a new set of batteries, produces bright light. As the batteries wear out:

Color changes to red and also intensity gets reduced

It stops working suddenly while giving white light

The light intensity gets reduced with no change in its color.

Light color changes first to yellow and then red with no change in intensity

Question 2 of 15

3. According to Maxwell’s hypothesis, changing of electric field give rise to:

Pressure gradient

Voltage

Charge

Magnetic field

Question 3 of 15

4. A coke coil has:

Low inductance and high resistance

Low inductance and low resistance

High inductance and high resistance

High inductance and low resistance

Question 4 of 15

5. In a circuit, the current lags behind the voltage by a phase difference of π/2, the circuit will contain which of the following:

Only C

Only L

R and C

Only R

Question 5 of 15

6. In the circuit shown below what will be the reading of the voltmeter and ammeter? (Total impedance of circuit Z = 100

Ω)

100 V, 2A

220 V, 2.2A

200 V, 1A

800 V, 2A

Question 6 of 15

7. The current gain for a transistor working as common base amplifier is 0.96. If the emitter current is 7.2 mA, the base current will be:

0.49 mA

0.29 mA

0.42 mA

0.35 mA

Question 7 of 15

8. If an AC main supply is given to be 220 v. The average emf during a positive half cycle will be

240 V

220√2 V

220 V

198 V

Question 8 of 15

9. An AC source of angular frequency ω is fed across a resistor R and a capacitor C in series. The current registered is I. If now the frequency of source is changed to ω/3 (but maintaining the same voltage), the current in the circuit is found to be halved. Calculate the ratio of reactance to resistance at the original frequency ω

√2/5

√4/5

√3/5

√1/5

Question 9 of 15

10. If the magnetic field of a light wave oscillates parallel to y-axis and is given by B_y = B_m sin (kz - ωt), the direction of wave travel and the axis along which the electric vector oscillates is:

- ve x – axis, y – axis

- ve z – axis, x – axis

- ve x – axis, z – axis

+ ve y – axis, z – axis

Question 10 of 15

11. An inductor coil of inductance L is cut into two equal parts and both the parts are connected in parallel. The net inductance is:

L/2

L/4

Question 11 of 15

12. In a AC circuit the voltage and current are described by V = 200 sin (319t – π/6) volts and i = 50sin (314t + π/6)mA respectively. The average power dissipated in the circuit is:

10.0 watts

2.5 watts

50.0 watts

5.0 watts

Question 12 of 15

13. A coil has an inductance of 0.7 Henry and is joined in series with a resistance of 220 Ω. When the alternating emf of 220 V at 50 Hz is applied to it then the phase through which current lags behind the applied emf and the wattles component of current in the circuit will be respectively

None of these

45°, 0.5 A

60°, 1.5 A

30°, 1A

Question 13 of 15

14. The pressure exerted by an electromagnetic wave of intensity 1 (watt/m²) on a non-reflecting surface is: [c is the velocity of light]

I/c

Ic²

I/c²

Question 14 of 15

15. Frequency of infrared wave is approximately:

10¹⁸ Hz

10¹⁶Hz

10⁹Hz

10¹⁴Hz

Question 15 of 15

Test Name	Alternating Current & Electromagnetic Waves Test
Subject	Physics
Test Type	MCQs
Total Question	15
Total Marks	30
Total Time	15 Mints
Test Help For	Physics Subject Test Prep. All Admissions Test. All Jobs Test prep. Medical Test prep. Engineering Test prep.

Test By Subject	Physics
Test By Topics	Physics Subject

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Physics

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