Two capacitors each of 1μF capacitance are connected in parallel and are then charged by 200 volts d.c. supply. The total energy of their charges (in joules) is
|
(a) 0.01 |
(b) 0.02 |
(c) 0.04 |
(d) 0.06 |
(c) 0.04
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and 
represents gravitational and electrostatic force respectively between electrons situated at a distance 10 cm. The ratio of 
is of the order of
|
(a) |
(b) 10 |
(c) 1 |
(d) |
A vertical wire kept in Z-X plane carries a current from Q to P (see figure). The magnetic field due to current will have the direction at the origin O along
|
(a) OX |
(b) |
(c) OY |
(d) |
Electroplating does not help in
|
(a) Fine finish to the surface |
(b) Shining appearance |
|
(c) Metals to become hard |
(d) Protect metal against corrosion |
The work function of a metal is 1.6 
J. When the metal surface is illuminated by the light of wavelength 6400 Å, then the maximum kinetic energy of emitted photo-electrons will be (Planck's constant h = 6.4 
)
|
(a) 14 |
(b) 2.8 |
(c) 1.4 |
(d) 1.4 |
Two condensers of capacities 2C and C are joined in parallel and charged upto potential V. The battery is removed and the condenser of capacity C is filled completely with a medium of dielectric constant K. The p.d. across the capacitors will now be
|
(a) |
(b) |
(c) |
(d) |
The value of stopping potential in the following diagram
|
(a) – 4V |
(b) – 3 V |
(c) – 2V |
(d) – 1 V |
