In a triode valve
|
(a) If the grid voltage is zero then plate current will be zero |
|
(b) If the temperature of filament is doubled, then the thermionic current will also be doubled |
|
(c) If the temperature of filament is doubled, then the thermionic current will nearly be four times |
|
(d) At a definite grid voltage the plate current varies with plate voltage according to Ohm’s law |
(c) If the temperature of filament is doubled, then the thermionic current will nearly be four times
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In P-N junction, avalanche current flows in circuit when biasing is
| (a) Forward | (b) Reverse | (c) Zero | (d) Excess |
Chromatic aberration of lens can be corrected by
|
(a) Reducing its aperature |
|
(b) Proper polishing of its two surfaces |
|
(c) Suitably combining it with another lens |
|
(d) Providing different suitable curvature to its two surfaces |
The frequency of 1st line of Balmer series in 
atom is 
. The frequency of line emitted by singly ionised He atom is
|
(a) 2 |
(b) 4 |
(c) |
(d) |
A negatively charged plate has charge density of 2 
. The initial distance of an electron which is moving toward plate, cannot strike the plate, if it is having energy of 200 eV
|
(a) 1.77 mm |
(b) 3.51 mm |
(c) 1.77 cm |
(d) 3.51 cm |
$\sqrt{6}$ times faster.
$\sqrt{6}$ times slower.
X-rays of wavelength 0.1 Å allowed to fall on a metal get scattered. The wavelength of scattered radiation is 0.111 Å. If h = 6.624 × 10–34 J-s and m0 = 9 × 10–31 kg, then the direction of the scattered photons will be
| (a) cos–1 (0.547) | (b) cos–1 (0.4484) | (c) cos–1 (0.5) | (d) cos–1 (0.3) |
Change Q on a capacitor varies with voltage V as shown in the figure, where Q is taken along the X-axis and V along the Y-axis. The area of triangle OAB represents
|
(a) Capacitance |
(b) Capacitive reactance |
|
(c) Magnetic field between the plates |
(d) Energy stored in the capacitor |
If in a plano-convex lens, the radius of curvature of the convex surface is 10 cm and the focal length of the lens is 30 cm, then the refractive index of the material of lens will be
|
(a) 1.5 |
(b) 1.66 |
(c) 1.33 |
(d) 3 |
A rectangular loop is being pulled at a constant speed v, through a region of certain thickness d, in which a uniform magnetic field B is set up. The graph between position x of the right hand edge of the loop and the induced emf E will be
(a)
|
(b)
|
(c)
|
(d)
|
