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.

621.

The critical angle for light traveling from a transparent medium to air s measured as 34º. The refractive index of the medium is

A.

0.56

B.

1.50

C.

1.79

D.

2.02

Correct answer is C

N = \(\frac{1}{sinθ}\)

  = \(\frac{1}{sin34}\)

  = 1.79

622.

A boy receives the echo of his clap reflected by a nearby hill 0.8s later. If the speed of sound in air is 340ms\(^-1\), how far is he from the hill?

A.

66m

B.

136m

C.

264m

D.

528m

Correct answer is B

2 × Distance = speed × time
2 × Distance = (340) × (0.8)

= 272/2
Distance = 136m

623.

A solid weighs 45N and 15N respectively in air and water. Determine the relative density of the solid

A.

0.33

B.

0.50

C.

1.50

D.

3.00

Correct answer is C

Weight in Air = 45N

  Weight in Water = 15N

  R.D = \(\frac{45}{45-15}\) = 1.50

624.

A resistor connected to a 12V battery draws a current of 2A. The energy dispatched in the resistor in 5 minutes is ___.

A.

3,600J

B.

6,000J

C.

7,200J

D.

14,400J

Correct answer is C

Power drawn by the resistor = IV = (2)(3) = 24W = 24J/s

  Energy dissipated = power × time = (24)(5)(60) = 7200J

625.

When a known standard resistor of 2.0 is connected to the 0.0cm end of a metre bridge, the balance point is found to be at 55.0cm

A.

1.10Ω

B.

1.64Ω

C.

2.44Ω

D.

27.50Ω

Correct answer is C

\(\frac{R_1}{R_2}\) = \(\frac{L_1}{(100 − L_1)}\)

  \(\frac{R_1}{2}\) = \(\frac{55}{45}\)

  R\(_1\) = 2 × \(\frac{55}{45}\)
= 2.44Ω