Explanation:
A Van de Graff generator, by means of a moving belt and suitable brushes, transfers charge continuously to a large spherical conducting shell. As a result, a potential difference of the order of several million volts is built up and this can be used for accelerating charged particles.
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With a change of load resistance of a triode, used as an amplifier, from 50 kilo ohms to 100 kilo ohms, its voltage amplification changes from 25 to 30. Plate resistance of the triode is
|
(a) 25 kW |
(b) 75 kW |
(c) 7.5 kW |
(d) 2.5 kW |
The relationship between λ and half life (
of a radioactive substance is
|
(a) λ = |
(b) λ = |
(c) λ = |
(d) λ = |
125 identical drops each charged to the same potential of 50 volts are combined to form a single drop. The potential of the new drop will be
|
(a) 50 V |
(b) 250 V |
(c) 500 V |
(d) 1250 V |
A group of N cells whose emf varies directly with the internal resistance as per the equation EN = 1.5 rN are connected as shown in the figure below. The current I in the circuit is
|
(a) 0.51 amp |
(b) 5.1 amp |
(c) 0.15 amp |
(d) 1.5 amp |
In a plano-convex lens the radius of curvature of the convex lens is 10 cm. If the plane side is polished, then the focal length will be (Refractive index = 1.5)
|
(a) 10.5 cm |
(b) 10 cm |
(c) 5.5 cm |
(d) 5 cm |
Assertion : The comet do not obey Kepler's laws of planetary motion
Reason : The comet do not have elliptical orbit
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
A 50 mH coil carries a current of 2 ampere. The energy stored in joules is
|
(a) 1 |
(b) 0.1 |
(c) 0.05 |
(d) 0.5 |
