An ideal coil of 10H is connected in series with a resistance of 5Ω and a battery of 5V. 2 seconds after the connection is made, the current flowing in amperes in the circuit is
(1-e)
e
e-1
e-1
A long straight wire of radius ‘a’ carries a steady current i. The current is uniformly distributed across its cross section. The ratio of the magnetic field at a/2 and 2 a is
1/4
4
1
1
A current I flows along the length of an infinitely long, straight, thin walled pipe. Then
the magnetic field is zero only on the axis of the pipe
the magnetic field is different at different points inside the pipe
the magnetic field at any point inside the pipe is zero
the magnetic field at any point inside the pipe is zero
Charges are placed on the vertices of a square as shown. Let E be the electric field and V the potential at the centre. If the charges on A and B are interchanged with those on D and C respectively, then
Both and V change
A charged particle with charge q enters a region of constant, uniform and mutually orthogonal fields , with a velocity
perpendicular to both
, and comes out without any change in magnitude or direction of
.Then
The potential at a point x (measured in µm) due to some changes situated on the x-axis is given by V (x) = 20 /x2- 4) volts. The electric field E at x = 4 µm is given by
5/3 Volt/µm and in the –ve x direction
5/3 Volt/µm and in the +ve x direction
10/9 Volt/µm and in the -ve x direction
10/9 Volt/µm and in the -ve x direction
Two identical conducting wires AOB and COD are placed at right angles to each other. The wire AOB carries an electric current I1 and COD carries a current I2. The magnetic field on a point lying at a distance ‘d’ from O, in a direction perpendicular to the plane of the wires AOB and COD, will be given by
The resistance of a wire is 5 ohm at 50°C and 6 ohm at 100°C. The resistance of the wire at 0 °C will be
2 ohm
1 ohm
4 ohm
4 ohm
C.
4 ohm
A parallel plate condenser with a dielectric of dielectric constant K between the plates has a capacity C and is charged to a potential V volts. The dielectric slab is slowly removed from between the plates and then reinserted. The net work done by the system in this process is
½ (K – 1) CV2
CV2 (K – 1) /K
(K –1) CV2
(K –1) CV2
If M0 is the mass of an oxygen isotope 8O17 , Mp and MN are the masses of a proton and a neutron respectively, the nuclear binding energy of the isotope is
(M0 – 8MP) C2
(M0 – 8MP – 9MN) C2
M0C2
M0C2