Two infinitely long parallel conducting plates having surface charge densities +σ and -σ respectively, are separated by a small distance. The medium between the plates is vacuum. If 
is the dielectric permittivity of vacuum, then the electric field in the region between the plates is
|
(a) 0 volts/meter |
(b) |
(c) |
(d) |
(c) 
volts/meter
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The fraction f of radioactive material that has decayed in time t, varies with time t. The correct variation is given by the curve
|
(a) A |
(b) B |
(c) C |
(d) D |
What should be the current in a circular coil of radius 5cm to annul 
|
(a) 0.4 A |
(b) 4 A |
(c) 40 A |
(d) 1 A |
The temperature at which thermal electric power of a thermo couple becomes zero is called
|
(a) Inversion temperature |
(b) Neutral temperature |
|
(c) Junction temperature |
(d) Null temperature |
What was the fissionable material used in bomb dropped at Nagasaki (Japan) in the year 1945 ?
|
(a) Uranium |
(b) Nepturium |
(c) Berkalium |
(d) Plutonium |
If there are n capacitors in parallel connected to V volt source, then the energy stored is equal to
|
(a) CV |
(b) |
(c) |
(d) |
A fuse wire with radius 1 mm blows at 1.5 amp. The radius of the fuse wire of the same material to blow at 3A will be
|
(a) |
(b) |
(c) |
(d) |
The capacitance of an air capacitor is 15 μF the separation between the parallel plates is 6mm. A copper plate of 3mm thickness is introduced symmetrically between the plates. The capacitance now becomes
|
(a) 5 μF |
(b) 7.5 μF |
(c) 22.5 μF |
(d) 30 μF |
The de-Broglie wavelength of a particle moving with a velocity 2.25 × 108 m/s is equal to the wavelength of photon. The ratio of kinetic energy of the particle to the energy of the photon is (velocity of light is 3 × 108 m/s)
|
(a) 1/8 |
(b) 3/8 |
(c) 5/8 |
(d) 7/8 |
