Albedo is maximum for
|
(a) Pluto |
(b) Venus |
(c) Earth |
(d) Mercury |
Albedo is maximum for
|
(a) Pluto |
(b) Venus |
(c) Earth |
(d) Mercury |
(b) Venus
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If a wire of resistance R is melted and recasted to half of its length, then the new resistance of the wire will be
|
(a) R/4 |
(b) R/2 |
(c) R |
(d) 2R |
A battery is charged at a potential of 15 V for 8 hours when the current flowing is 10 A. The battery on discharge supplies a current of 5 A for 15 hours. The mean terminal voltage during discharge is 14 V. The "Watt-hour" efficiency of the battery is
|
(a) 82.5% |
(b) 80 % |
(c) 90% |
(d) 87.5% |
The net resistance of a voltmeter should be large to ensure that
|
(a) It does not get overheated |
|
(b) It does not draw excessive current |
|
(c) It can measure large potential difference |
|
(d) It does not appreciably change the potential difference to be measured |
A non-conducting solid sphere of radius R is uniformly charged. The magnitude of the electric field due to the sphere at a distance r from its centre
|
(a) Increases as r increases for r < R |
(b) Decreases as r increases for 0 < r < ∞ |
|
(c) Decreases as r increases for R < r < ∞ |
(d) a, c |
In the circuit as shown in the figure the effective capacitance between A and B is

|
(a) 3 μF |
(b) 2 μF |
(c) 4 μF |
(d) 8 μF |
A galvanometer has a resistance of 25 ohm and a maximum of 0.01 A current can be passed through it. In order to change it into an ammeter of range 10 A, the shunt resistance required is
|
(a) 5/999 ohm |
(b) 10/999 ohm |
(c) 20/999 ohm |
(d) 25/999 ohm |
An electron is revolving round a proton, producing a magnetic field of 16 weber/m2 in a circular orbit of radius 1Å. It’s angular velocity will be
|
(a) 1017 rad/sec |
(b) 1/2 π × 1012 rad/sec |
|
(c) 2π × 1012 rad/sec |
(d) 4 π × 1012 rad/sec |
If an object is placed 10 cm infront of a concave mirror of focal length 20 cm, the image will be
|
(a) Diminished, upright, virtual |
(b) Enlarged, upright, virtual |
|
(c) Diminished, inverted, real |
(d) Enlarged, upright, real |