- AIs different for different metals.
- BIs same for all metals.
- CDepends upon the intensity of incident light.
- DDepends upon the frequency of incident light.
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A uniform wire of resistance R is uniformly compressed along its length, until its radius becomes n times the original radius. Now resistance of the wire becomes
|
(a) |
(b) |
(c) |
(d) nR |
AB is a wire of uniform resistance. The galvanometer G shows no current when the length AC = 20cm and CB = 80 cm. The resistance R is equal to
|
(a) 2 Ω |
(b) 8 Ω |
(c) 20 Ω |
(d) 40 Ω |
The resistance of a metal wire increases with increasing temperature on account of:
The work function for metals A, B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein’s equation, the metals which will emit photo electrons for a radiation of wavelength 4100 Å is/are
|
(a) None of these |
(b) A only |
(c) A and B only |
(d) All the three metals |
$\frac{\text{v}}{4}$
$\frac{\text{v}}{2}$
$\text{v}$
$2\text{v}$
An object is placed first at infinity and then at 20 cm from the object side focal plane of the convex lens. The two images thus formed are 5 cm apart. The focal length of the lens is
|
(a) 5 cm |
(b) 10 cm |
(c) 15 cm |
(d) 20 cm |