A cell can be balanced against 110 cm and 100 cm of potentiometer wire, respectively with and without being short-circuited through a resistance of 10 Ω. Its internal resistance is
1.0 Ω
0.5 Ω
2.0 Ω
2.0 Ω
The velocity of electromagnetic radiation in a medium of permittivity and permeability is given by
A long solenoid has 500 turns. When a current of 2 A is passed through it, the resulting magnetic flux linked with each turn of the solenoid is 4 x 10-3 Wb. The self -inductance of the solenoid is
2.5 H
2.0 H
1.0 H
1.0 H
C.
1.0 H
The inductance of a coil is numerically equal to the emf induced in the coil when the current in the coil changes at the rate of 1 As-1. If I is the current flowing in the circuit, then flux linked with the circuit is observed to be proportional to I, ie,
where L is called the self-inductance or coefficients of self-inductance or coefficient of self-inductance or simply inductance of the coil.
Net flux through the solenoid.
Φ = 500 x 4 x 10-3 = 2 Wb
Or 2 = L x 2 [after putting value in eq. or L = 1H]
In an AC circuit, the emf (e) and the current (i) at any instant are given respectively by
e = E0 sin ωt
i = Io sin (ωt -Φ)
The average power in the circuit over one cycle of AC is
In the circuit shown, the current through the 4 Ω resistor is 1 A when the points P and M are connected to a DC voltage source. The potential difference between the point M and N is
1.5 V
1.0 V
0.5 V
0.5 V
A circular disc of radius 0.2 m is placed in a uniform magnetic field of induction in such a way that its axis makes an angle of 60o with. The magnetic flux linked with the disc is
0.02 Wb
0.06 Wb
0.05 Wb
0.05 Wb
Curie temperature is the temperature above which
ferromagnetic material becomes paramagnetic material
paramagnetic material becomes diamagnetic material
paramagnetic material becomes ferromagnetic material
paramagnetic material becomes ferromagnetic material
A galvanometer of resistance 50 Ω is connected to a battery of 3 V along with a resistance of 2950 Ω in series. A full-scale deflection of 30 divisions is obtained in the galvanometer. In order to reduce this deflection to 20 divisions, the resistance in series should be
5050 Ω
5550 Ω
6050 Ω
6050 Ω
The work function of a surface of a photosensitive material is 6.2 eV. The wavelength of the incident radiation for which the stopping potential is 5 V lies in the
ultraviolet region
visible region
infrared region
infrared region
The ground state energy of hydrogen atom is -13.6 eV. When its electron is in the first excited state, its excitation energy is
3.4 eV
6.8 eV
10.2 eV
zero