CBSE
Multiple Choice QuestionsAssertion: An electric field is preferred in comparison to magnetic field for detecting the electron beam in a television picture tube.
Reason: Electric field requires low 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.
Four charges arc arranged at the corners of a square as shown in the figure. The direction of electric field at the centre of the square is along
DC
BC
AB
AD
Electric field at the centre of a uniformly charged semicircle of radius a is
Two changes +q and -q are attached to the two ends of a light rod of length L, as shown in figure. The system is given a velocity ν perpendicular to magnetic field . The magnetic force on the system of charges and magnitude of force on one charge by the rod, are respectively
zero, zero
zero, qvB
2qvB, 0
2qvB, qvB
A charge q is uniformly distributed on a ring of radius r. A sphere of an equal radius is constructed with its centre lying on the periphery of the ring. The flux of electric field through the surface of the sphere will be
In a case of infinite long wire electric field is proportional to
r0
Assertion: In a cavity within a conductor, the electric field is zero.
Reason: Charges in a conductor reside only at its surface.
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
Two parallel large thin metal sheets have equal surface charge densities ( σ = 26.4 × 10-12 C/m2 ) of opposite signs. The electric field between these sheets is
1.5 N/C
1.5 × 10-10 N/C
3 N/C
3 × 10-10 N/C
The spatial distribution of the electric field due to two charges (A, B) is shown in figure. Which one of the following statements is correct?
A is +ve and +B is -ve and
A is ve and B is +ve;
both are +ve but A > B
both are ve but A > B
Using mass (M), length (L), time (T ) and current (A) as fundamental quantities, the dimension of permeability is
[ M-1 L T-2 A ]
[ M L2 T-2 A-1 ]
[ M L T-2A-2 ]
[ M L T-1 A-1 ]
