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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.

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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

4.0 x 10¹⁴Hz

6.0 x 10¹⁴Hz

7.5 x 10¹⁴Hz

9.0 x 10¹⁴Hz

View answer & explanation

Correct answer is A

1.5 = $\frac{6 \times 10^{14}}{F}$

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

the focal length

two times the focal length

the distance of the image

two times the radius of curvature

View answer & explanation

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

200Hz

400Hz

800Hz

1600Hz

View answer & explanation

Correct answer is B

F = $\frac {1}{2L}$ $\sqrt\frac{T}{m}$

T₂ = 4T₁ ; L₂ = 2L₁

$\frac{2F_1L_1}{2F_2L_2}$ = $\sqrt\frac{T_1}{T_2}$

$\frac{400\times L_1}{F \times L_1}$ = $\sqrt\frac{T_1}{4T_1}$

F = 400Hz