Question 3

The photoelectric cut-off voltage in a certain experiment is 1.5 V. What is the maximum kinetic energy of photoelectrons emitted?

Answer

Photoelectric cut-off voltage, V_{0} = 1.5 V

The maximum kinetic energy of the emitted photoelectrons is given as: *K _{e} = eV_{o}*

Where,

e = Charge on an electron = 1.6 × 10^{−19} C

∴ K_{e} = 1.6 x 10^{-19} x 1.5 = 2.4 x 10^{-19} J

*Therefore, the maximum kinetic energy of the photoelectrons emitted in the given experiment is 2.4 × 10 ^{−19} J.*

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(b) Is there a transfer of mass from wool to polythene?

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A regular hexagon of side 10 cm has a charge 5 µC at each of its vertices. Calculate the potential at the centre of the hexagon.

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A point charge of 2.0 μC is at the centre of a cubic Gaussian surface 9.0 cm on edge. What is the net electric flux through the surface?

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The electrostatic force on a small sphere of charge 0.4 μC due to another small sphere of charge − 0.8 μC in air is 0.2 N.

(a) What is the distance between the two spheres?

(b) What is the force on the second sphere due to the first?

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The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is B

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A 3.0 cm wire carrying a current of 10 A is placed inside a solenoid perpendicular to its axis. The magnetic field inside the solenoid is given to be 0.27 T. What is the magnetic force on the wire?

- Q:-
Two charges 5 x 10

^{-8}C and -3 x 10^{-8}C are located 16 cm apart. At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero. - Q:-
A polythene piece rubbed with wool is found to have a negative charge of 3 × 10

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(b) Is there a transfer of mass from wool to polythene?

Ambily
2019-01-28 22:00:48

Thanq you so much

- NCERT Chapter

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