If there were no atmosphere, the average temperature on earth surface would be
lower
higher
same
0°C
Assertion: The alternating current lags behind the e.m.f. by a phase angle of /2, when AC flows through an inductor.
Reason: The inductive reactance increases as the frequency of AC source decreases.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: A spark occur when the poles of a switch when the switch is opened.
Reason: Current flowing in the conductor produces magnetic field.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: X-rays can penetrate through the flesh but not through the bones.
Reason: The penetrating power of X-rays depends on voltage.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: We cannot think of magnetic field configuration with three poles.
Reason: A bar magnet does exert a torque on itself to its own field.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
D.
If both assertion and reason are false
It is quite clear that magnetic poles always exists in pairs. Since, one can imagine magnetic field configuration with three poles. When north poles or south poles of two mangets are glued together. They provide a three pole field configuration. It is also know that a bar magnet does not exert a torque on itself due to its own field.
Assertion: A bird perches on a high power line and nothing happens to the bird.
Reason: The level of bird is very high from the ground.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: Inductance coils are usually made of thick copper wire.
Reason: Induced current is more in wire having less resistance.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: When a radius of circular loop carrying current is doubled, its magnetic moment becomes four times.
Reason: Magnetic moment depends on area of the loop.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: In the following circuit, emf is 2 V and internal resistance of the cell is I Ω and R= 1 Ω, then reading of the voltmeter is 1 V.
Reason: V = E IR where E = 2V, I = 2/2 = 1A
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: A domestic electrical appliance, working on a three pin will continue working even if the top pin is removed.
Reason: The third pin is used only as a safety device.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.