The grid in a triode valve is used
|
(a) To increases the thermionic emission |
|
(b) To control the plate to cathode current |
|
(c) To reduce the inter-electrode capacity |
|
(d) To keep cathode at constant potential |
(b) To control the plate to cathode current
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Monochromatic green light of wavelength 5 
illuminates a pair of slits 1 mm apart. The separation of bright lines on the interference pattern formed on a screen 2 m away is
|
(a) 0.25 mm |
(b) 0.1 mm |
(c) 1.0 mm |
(d) 0.01 mm |
A conducting sphere of radius R = 20 cm is given a charge Q = 16μC. What is 
at centre
|
(a) 3.6 |
(b) 1.8 |
(c) Zero |
(d) 0.9 |
A metallic shell has a point charge ‘q’ kept inside its cavity. Which one of the following diagrams correctly represents the electric lines of forces
|
(a)
|
(b)
|
(c)
|
(d)
|
Two particles A and B of masses 
and 
respectively and having the same charge are moving in a plane. A uniform magnetic field exists perpendicular to this plane. The speeds of the particles are 
and 
respectively, and the trajectories are as shown in the figure. Then
|
(a) |
(b) |
|
(c) |
(d) |
For a thermocouple the neutral temperature is 270℃ when its cold junction is at 20℃. What will be the neutral temperature and the temperature of inversion when the temperature of cold junction is increased to 40 ℃
|
(a) 290℃, 580℃ |
(b) 270℃, 580℃ |
(c) 270℃, 500 ℃ |
(d) 290 ℃, 540 ℃ |
Two lines of force due to a bar magnet
|
(a) Intersect at the neutral point |
|
(b) Intersect near the poles of the magnet |
|
(c) Intersect on the equatorial axis of the magnet |
|
(d) Do not intersect at all |
