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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.

2,886.

Light of frequency 6.0 x 1014 Hz travelling in air is transmitted through glass or refractive index 1.5. Calculate the frequency of the light in the glass

A.

4.0 x 1014Hz

B.

6.0 x 1014Hz

C.

7.5 x 1014Hz

D.

9.0 x 1014Hz

Correct answer is A

1.5 = 6×1014F

F = 4 x 1014Hz

2,887.

To produce a parallel beam of light from a concave mirror, the distance at a which the lamp should be placed from the mirror is equal to

A.

the focal length

B.

two times the focal length

C.

the distance of the image

D.

two times the radius of curvature

Correct answer is A

No explanation has been provided for this answer.

2,888.

The note produced by a stretched string has a fundamental frequency of 400Hz. If the length of the string is doubled while the tension in the string is increased by a factor of 4, the frequency is

A.

200Hz

B.

400Hz

C.

800Hz

D.

1600Hz

Correct answer is B

F = 12L Tm

T2 = 4T1 ; L2 = 2L1

2F1L12F2L2 = T1T2

400×L1F×L1 = T14T1

F = 400Hz

2,889.

A pipe of length 45cm is closed at the end. Calculate the fundamental frequency of the sound wave generated in the pipe if the velocity of sound in air is 360ms-1 [Neglect end correction]

A.

5.5Hz

B.

148.5Hz

C.

200.0Hz

D.

550.0Hz

Correct answer is C

λ = 4L = 4 X 45 = 180cm

F = Vλ

= 360180×102

= 200Hz

2,890.

The fundamental frequency of vibration of a sonometer wire may be halved by

A.

doubling the length of the wire

B.

doubling the mass of the wire

C.

reducing the tension by half

D.

reducing the absolute temperature by half

Correct answer is A

F α 1L