Assertion (A): The electric field due to a charge configuration with total charge zero may not be zero.
Reason (R): Electric field obeys the principle of superposition.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
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Assertion (A) is true: An electric dipole has zero net charge but produces a non-zero electric field. Reason (R) is true: Electric fields add vectorially due to superposition. (R) correctly explains (A) because individual fields from component charges, even if their sum is zero, combine vectorially to form a net non-zero field.
Assertion (A): Vehicles carrying highly inflammable materials have hanging chains, slightly touching the ground.
Reason (R): The body of a vehicle gets charged when moving through air at high speed.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
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Assertion (A) is true: These chains are a safety measure to discharge static electricity. Reason (R) is true: Friction between the vehicle's body and air (or tires and road) generates static charge.
(R) correctly explains (A) as the chains provide a path to ground, preventing dangerous sparks from static charge buildup.
Assertion (A): The tyres of aeroplanes are slightly conducting.
Reason (R): During take off and landing of aeroplanes, the friction between tyres and the runway may cause electrification of tyres.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
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Assertion (A) is true: Conducting tyres prevent hazardous static charge accumulation. Reason (R) is true: Friction during takeoff and landing causes static electrification.
(R) correctly explains (A) because the conducting tyres allow the generated static charge to safely discharge into the runway, preventing sparks and potential ignitions.
Assertion (A): We can shield a charge from electric fields by putting it inside a hollow conductor but we can not shield a body from the gravitational influence of near by matter by putting it inside a hollow sphere.
Reason (R): Gravitational force in between two point mass bodies is independent of the intervening medium them.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
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Assertion (A) is true: Electrostatic shielding (Faraday cage) works, but gravitational shielding does not. Reason (R) is true: Gravitational force is a fundamental interaction that is unaffected by the medium. (R) correctly explains (A) as electric fields can be screened by charge redistribution in conductors, a mechanism not available for gravity.
Assertion (A): If X-ray is allowed to fall on uncharged gold leaf in evacuated glass chamber of electroscope, leaves will diverge.
Reason (R): Uncharged gold leaves will get charged positively when x-ray falls on it.
1. (1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. (2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (3) (A) is true but (R) is false
4. (4) Both (A) and (R) are false
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X-rays have sufficient energy to eject electrons from the gold leaves (photoelectric effect), leaving them positively charged. The like positive charges on the leaves cause them to repel and diverge. Thus, (R) correctly explains (A).
Assertion (A): Excess charge on a conductor resides entirely on the outer surface.
Reason (R): Like charges repel each other.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
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Assertion (A) is true. Excess charges on a conductor spread out on the outer surface due to mutual repulsion. Reason (R) is also true, as like charges repel. (R) correctly explains (A).