Electric potential at a distance r from the point charge is proportional to
1. \(r^2\)
2. r-1
3. r0
4. r+1
1. \(r^2\)
2. r-1
3. r0
4. r+1
2. r-1
The electric potential due to point charge 3 nC at distance of 9 cm is
(a) 270 v
(b) 3 v
(c) 300 v
(d) 30 v
Why are electric field lines perpendicular at a point on an equipotential surface of a conductor ?
Why must electrostatic field at the surface of a charged conductor be normal to the surface at every point ? Give reason.
A coil of N turns and mean cross-sectional area A is rotating with uniform angular velocity ω about an axis at right angle to uniform magnetic field B. The induced emf in the coil will be
(a) NBAsinωt
(b) NBωsinωt
(c) NB/Asinωt
(d) NBAωsinωt
The electric potential of earth is taken as:
(a) zero
(b) infinity
(c) unity
(d) None of these
What is the SI unit of electric potential?
(a) J/C
(b) J-C
(c) v-m
(d) J/c-m
Three capacitors 3 μF, 6 μF and 6 μF are connected in series to a source of 120 volt. The potential difference across the 3 μF capacitor will be
(a) 40 volt
(b) 30 volt
(c) 40 volt
(d) 60 volt
A resistance of R Ω draws current from a potentiometer. The potentiometer has a total resistance \(R_0\) Ω as shown in the Fig below. A voltage V is supplied to the potentiometer. Derive an expression for the voltage across R when the sliding contact is in the middle of the potentiometer.
Which of the following is correct for light diverging from a point source?
(a) The intensity decreases in proportion with the distance squared.
(b) The wave front is parabolic.
(c) The intensity at the wavelength does not depend on the distance.
(d) None of these.
In interference pattern, the energy is
A) created at maximum
(B) destroyed at minimum
(C) conserves but re-disturbed
(D) none of the above