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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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1,496.

Which of the following particles are termed nucleons in a neutral atom?

protons and neutrons

neutrons and electrons

protons and electrons

protons, electrons and neutrons

View answer & explanation

Correct answer is A

No explanation has been provided for this answer.

1,497.

The minimum energy required to cause photoelectric emission when the surface of a metal is irradiated with electromagnetic radiation of suitable frequency is called

critical energy

ionization energy

work function

planck's constant

View answer & explanation

Correct answer is C

No explanation has been provided for this answer.

1,498.

The work function of a metal is 2.56 x 10^-19J. Calculate the frequency of a photon whose energy is required to eject from the metal an electron with kinetic energy of 3.0ev. [1 eV = 1.6 x 10^-19J, h = 6.6 x 10^-34Js]

5.56 x 10¹⁹Hz

1.66 x 10¹⁹Hz

1.12 x 10¹⁵Hz

8.42 x 10¹⁴Hz

View answer & explanation

Correct answer is C

F = $\frac{K.E + Wo}{h}$

= $\frac{3.0 \times 1.6 \times 10^{-19} + 2.56 \times 106{-19}}{6.6 \times 106{-34}}$

- 1.12 x 10^-15HZ

1,499.

A coil of inductance 0.12 H and resistance 4 $\Omega$ , is connected across a 240V, 50Hz supply. Calculate the current through it. [ $\pi$ = 3.142]

6.3A

33.3A

37.2A

40.0A

View answer & explanation

Correct answer is A

XL = $2\pi f L$

= = 2 x 3.142 x 50 x 0.12

= 37.68 $\Omega$

Z = $\sqrt{R^2 + X_L^2} = \sqrt{4^2 + 37.68^2}$

I = $\frac{V}{z} = \frac{240}{37.89}$

= 6.3A