When a given coil is connected to a 200V, 50 Hz AC source, 1 A current flows in the circuit. The inductive reactance of the coil used is
When a given coil of ohmic resistance 100 Ω and inductive reactance 100 Ω is connected to a 200 V DC source, the current flows in the circuit is
1 A
1.5 A
2 A
Ω
Two point charges + q and + 4q are located at x = O and x = L respectively. The location of a point on the x-axis at which the net electric field due to these two points charges is zero, is
L / 3
2 L
4 L
8 L
If electric flux entering and leaving an enclosed surface is and respectively, the electric charge inside the enclosed surface will be
In a potentiometer experiment, the balancing with a cell is at 240 cm. On shunting the cell with a resistance of 2 Ω the balancing length becomes 120 cm. The internal resistance of the cell is
0.5 Ω
1 Ω
2 Ω
4 Ω
A place where the vertical component of the earth's magnetic field is zero has angle of dip is
45°
90°
0°
60°
A.
45°
A tank is filled with water to a height of 12.4 cm. The apparent depth of a needle lying at the bottom of the tank is measured by a microscope to be 9.3 cm. If water is replaced by a liquid of refractive index 1.6 upto the same height, by what distance would the microscope have to be moved to focus on the needle again
4 cm
3 cm
2.18 cm
1.55 cm
A ray of light falls on a transparent right-angled isosceles prism made from a glass of refractive index . The incident ray falls normally on one of the equal sides of this prism. The ray will suffer
total internal reflection
Interference
refraction with angle of refraction 90°
None of the above
The magnifying power of a telescope in its normal adjustment is 20. If the length of the telescope is 105 cm in this adjustment, the focal length of the objective lens is
100 cm
5 cm
80 cm
95 cm