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Physics questions and answers

Physics Questions and Answers

If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.

496.

An alternating current can induce voltage because it has

A.

ripple value

B.

varying magnetic field

C.

weaker magnetic field than direct current

D.

high peak value

Correct answer is B

As induced voltage is produced by varying magnetic field. The induced voltage is proportional to the rate of change of magnetic flux linking the coil.

497.
498.

A vibrator causes water ripples to travel across the surface of a tank. The wave travels 50cm in 2s and the distance between successive crests is 5cm. Calculate the frequency of the vibrator

A.

5Hz

B.

6Hz

C.

5.2Hz

D.

25Hz

Correct answer is A

V=Distancetime

= 50cm2s

= 25 cms1.


V=fλ

f=Vλ

f=255

= 5 Hz

 

499.

A supply of 400V is connected across capacitors of 3μf and 6μf in series. Calculate the charge

A.

8 x 104C

B.

4 x 102C

C.

8 x 103C

D.

4 x 108C

Correct answer is A

CT = C1 × C2
C1 + C2

 

= 3 × 6
3 + 6


= 189 = 2μf
Q = CV
⇒ 2 × 106 × 400
⇒ 800 × 106C = 8 × 104C

500.

The diagram above represents the stress-strain graph of a loaded wire. Which of these statements is correct?

A.

At J, the wire becomes plastic

B.

J is the yield point

C.

L is the elastic limit

D.

At K, the wire breaks

Correct answer is B

- I is the elastic limit
- the end of the constant part J is the yield point
- L is the break point.