A and B are two points on a uniform ring of resistance R. The ∠ ACB = 0, where C is the centre of the ring. The equivalent resistance between A and B is
A square loop ABCD, carrying a current I2, is placed near and coplanar with a long straight conductor XY carrying a current I1, as shown in figure. The net force on the loop will be
A circular coil of radius 10 cm, 500 turns and resistance 2 Ω is placed with its plane perpendicular to the horizontal component of the earth's magnetic field. It is rotated about its vertical diameter through 180° in 0.25 s. The
current induced in the coil is
(Horizontal component of the earth's magnetic field at that place is 3.0 x 10-5 T)
1.9 × 10-3 A
2.9 × 10-3 A
3.9 × 10-3 A
4.9 × 10-3 A
A parallel plate capacitor with air as a dielectric has capacitance C. A slab of dielectric constant K, having same thickness as the separation between the plates is introduced so as to fill one-fourth of the capacitor as shown in the figure. The new capacitance will be
A.
The two condensers with Kand with air are in parallel.
With air
C1 =
C1 =
With medium
C2 =
C2 =
∴ C' = C1 + C2
=
C' =
⇒ C' =
In the circuit shown in figure, if A the diode forward voltage is 0.3 V, the voltage difference between A and B is
1.3 V
2.3 V
0
0.5 V
Assertion: Acceleration of charged particle in non-uniform electric field does not depend on velocity of charged particle.
Reason: Charge is an invariant quantity. That is amount of charge on particle does not depend on frame of reference.
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: If a dielectric is placed in external field then field inside dielectric will be less than applied field.
Reason: Electric field will induce dipole moment opposite to field direction.
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: An electrical bulb starts glowing instantly as it is switched on.
Reason: Drift speed of electrons in a metallic wire is very large.
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
A 2.0 cm tall object is placed 15 cm in front of a concave mirror of focal length 10 cm. What is the size and nature of the image?
4 cm, real
4 cm, virtual
1.0 cm, real
none of these
The least distance of vision of a longsighted person is 60 cm. By using a spectacle lens, this distance is reduced to 12 cm. The power of the lens is
+ 0.5 D
+ ( 20/30 ) D
(10/3) D
+ 2.0 D