In the above diagram \(C_2\) is twice of Capacitance of \(C_1\) which is C. Find the ratio of energy stored in the combination before and after the insertion of of a dielectric constant K in both the capacitors.(Battery is disconnected)
1. K:1
2. 1:K
3. 1:K2
4. 1:1
1. K:1
2. 1:K
3. 1:K2
4. 1:1
1. K:1
Two capacitors of capacitance 6 µF and 4 µF are put in series across a 120 V battery. What is the potential difference across the 4 µF capacitor?
(a) 72 V
(b) 60 V
(c) 48 V
(d) zero
Four point charges –Q,-q,2q,2Q are placed at different corners of a square . The relation between Q and q for which the potential at the center of the square is zero
1.Q=q
2.Q=1/q
3.Q=-q
4. Q=-1/q
Three capacitors of 6μf each are connected across a triangle. What is the resultant capacitance across any side of the triangle.
1. 6 μf
2. 2 μf
3. 4 μf
4. 12μf
A capacitor of 4 μF is connected as shown in the circuit Figure. The internal resistance of the battery is 0.5 Ω. The amount of charge on the capacitor plates will be :
An air capacitor is charged with an amount of charge q and dipped into an oil tank. If the oil is pumped out, the electric field between the plates of capacitor will
(a) increase
(b) decrease
(c) remain the same
(d) becomes zero
A parallel plate capacitor is made by stacking n equally spaced plates connected alternately. If the capacitance between any two plates is C, then the resultant capacitance is
(a) C
(b) nC
(c) (n-1)C
(d) (n+1)C
Two point charges q and –2q are kept d distance apart. Find the location of the point relative to charge q at which potential due to this system of charges is zero.
A square loop of side l , resistance R is placed in a uniform magnetic field B acting normally to the plane of the loop. If we attempt to pull it out of the field with a constant velocity v , then the power needed is
(a) BRlv
(b) B²l²v²/R
(c) B l²v²/ R
(d) Blv/R
According to Huygens, medium through which light travel is
(A) vacuum only
(B) luminiferous either
(C) liquid only
(D) solid only
An electric charge of 425 f μC is removed from a fully charged capacitor of capacitance 8.5μF. Its potential will be lowered by:
(a) 75 V
(b) 100 V
(c) 85 V
(d) 50 V
If 100 J of work has to be done in moving an electric charge of 4 C from a place, where potential is -10 volt to another place where potential is V volt,find the value of V.
(a) 5 V
(b) 10 V
(c) 25 V
(d) 15 V
The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 A is of the order of
(a) \(10^6\) rad
(b) \(10^{-2}\) rad
(c) \(10^{-4}\) rad
(d) \(10^{-6}\) rad
Magnetic field lines form continuous closed loops
a) magnet is always a dipole
b) magnet is always a monopole
c) magnetic material is permeable
d) none of the above
When a soap bubble is given an electric charge
(A) It contracts
(B) It expands
(C) Its size remains the same
(D) It expands or contracts depending upon whether the charge is positive or negative