A negatively charged oil drop is prevented from falling under gravity by applying a vertical electric field 100 V/m. If the mass of the drop is 1.6 x \(10^{-3}\)g, the number of electrons carried by the drop is (g=10m/\(s^2\))
(A)\(10^{18}\)
(B)\(10^{15}\)
(C)\(10^{12}\)
(D)\(10^9\)
(A)\(10^{18}\)
(B)\(10^{15}\)
(C)\(10^{12}\)
(D)\(10^9\)
(C)\(10^{12}\)
Cathode rays travelling from west to east enter into region of electric field directed towards south to north in the plane of paper. The deflection of cathode rays is towards:
(A) East
(B) West
(C) North
(D) South
The insulation property of air, breaks down at E=3x \(10^6\)V/m. The maximum charge that can be given to a sphere of radius 2.5 m is approximately
(A) 2x \(10^{-2}\)C
(B) 2x \(10^{-3}\)C
(C) 3x \(10^{-6}\)C
(D) 3x \(10^{-5}\)C
What is the angle between the electric dipole moment and electric field strength due to it on the axial line?
(A) \(0^\circ\)
(B) \(90^\circ\)
(C) \(180^\circ\)
(D) None of these
Two-point charges 2μC and 4μC are placed 2 cm apart. The ratio of the Coulomb’s force experienced by them is
(A) 1: 2
(B) 2: 1
(C) 1: 1
(D) 4: 1
what is the angle between an electric dipole moment and then electric field strength due to it on its equatorial line?
(A) \(0^\circ\)
(B) \(90^\circ\)
(C) \(180^\circ\)
(D) None of these
If a charge q is placed at the center of the line joining two equal charges Q such that the system is in equilibrium, then the value of q is
(A)Q/2
(B)-Q/2
(C)Q/4
(D)-Q/4
A charge + Q, is uniformly distributed within a sphere of radius R. Find the electric field, due to this charge distribution, at a distant point r from the centre of the sphere where :
(i) 0 < r < R
(ii) r > R
For any charge configuration equipotential surface through a point is normal to the electric field.
1. Since W=Fscosθ is zero so field is normal to the surface
2. As W≠0
3. Work done can be Zero if Field is parallel to the field
4. None of these
A 40 mF capacitor is connected to a 200 V, 50 Hz ac supply. The r.m.s value of the current in the circuit is, nearly
(a) 1.7 A
(b) 2.05 A
(c) 2.5 A
(d) 25.1 A
Equal potentials are applied on an iron and copper wire of same length. In order to have same current flow in the wire, the ratio
The fringe width (β) of a diffraction pattern and the slit width d are related as:
(a) β ∝ d
(b) β ∝1/d
(c) β ∝ √d
(d) β ∝ 1/\(d^2\)
Ratio of intensities of two waves are given by 4 :1. Then the ratio of the amplitudes of the two waves.
(a) 2 : 1
(b) 1 : 2
(c) 4 : 1
(d) 1 : 4
If the angle of dip at two places are 30° and 45° respectively, then the ratio of horizontal components of the earth’s magnetic field at the two places will be
According to Huygens, medium through which light travel is
(A) vacuum only
(B) luminiferous either
(C) liquid only
(D) solid only