- AAttractive
- BRepulsive
- CBoth attractive and repulsive
- DNeither attractive nor repulsive
Explanation:
If electric current in two long straight conductors is in mutually opposite directions, the magnetic force acting between them will be repulsive.
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According to Einstein's photoelectric equation, the graph between the kinetic energy of photoelectrons ejected and the frequency of incident radiation is
(a)
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(b)
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(c)
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(d)
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Penetrating power of X-rays can be increased by
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(a) Increasing the potential difference between anode and cathode |
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(b) Decreasing the potential difference between anode and cathode |
| (c) Increasing the cathode filament current |
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(d) Decreasing the cathode filament current |
$\lambda_\text{e}=\lambda_\text{p}.$
$\lambda_\text{e}<\lambda_\text{p}.$
$\lambda _\text{e}>\lambda_\text{p}.$
The relation between
In a potentiometer circuit there is a cell of e.m.f. 2 volt, a resistance of 5 ohm and a wire of uniform thickness of length 1000 cm and resistance 15 ohm. The potential gradient in the wire is
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(a) |
(b) |
(c) |
(d) |
A radio transmitter radiates 1 kW power at a wavelength 198.6 metres. How many photons does it emit per second
|
(a) |
(b) |
(c) |
(d) |
According to classical theory, the circular path of an electron in Rutherford atom is
|
(a) Spiral |
(b) Circular |
(c) Parabolic |
(d) Straight line |
In an electron gun the control grid is given a negative potential relative to cathode in order to
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(a) Decelerate electrons |
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(b) Repel electrons and thus to control the number of electrons passing through it |
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(c) To select electrons of same velocity and to converge them along the axis |
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(d) To decrease the kinetic energy of electrons |
The number of electrons to be put on a spherical conductor of radius 0.1m to produce an electric field of 0.036 N/C just above its surface is
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(a) 2.7 |
(b) 2.6 |
(c) 2.5 |
(d) 2.4 |