A choke is preferred to resistance for limiting current in AC circuit because
choke is cheap
there is no wastage of power
choke is compact in size
choke is a good absorber of heat
A current of 6 A enters one comer P of an equilateral triangle PQR having 3 wires of resistances 2Q each and leaves by the corner R. Then the current I1 and I2 are
2 A, 4 A
4 A, 2 A
1 A, 2 A
2 A, 3 A
All components of the electromagnetic spectrum in vacuum have the same
energy
velocity
wavelength
frequency
In the Wheatstone's network given, P = 10Ω, Q = 20Ω, R =15Ω, S = 30Ω, the current passing through the battery (of negligible internal resistance) is
0.36 A
zero
0.18 A
0.72 A
A.
0.36 A
The balanced condition for Wheatstone's bridge is
As it's a balanced Wheatstone bridge, no current flows through the galvanometer. Now, P and R are in series, so resistance
R1 = P + R
= 10 + 15 = 25Ω
Similarly, Q and S are in series, so resistance
R2 = Q + S
= 20 + 30 = 50Ω
Net resistance of the network as R1and R2 are in parallel
A proton and a deuteron with the same initial kinetic energy enters a magnetic field in a direction perpendicular to the direction of the field. The ratio of the radii of the circular trajectories described by them is
1 : 4
1 : √2
1 : 1
1 : 2
Two identical capacitors each of capacitance 5 µF are charged to potentials 2 kV and 1 kV respectively. Their -ve ends are connected together. When the +ve ends are also connected together, the loss of energy of the system is
160 J
Zero
5 J
1.25 J
An inductance of , a capacitance of and a resistance of 10Ω are connected in series with an AC source 220 V, 50 Hz. The phase angle of the circuit is
A step-down transformer reduces the voltage of a transmission line from 2200 V to 220 V. The power delivered by it is 880 W and its efficiency is 88%. The input current is
4.65 mA
0.045 A
0.45 A
4.65 A
A beam of light of wavelength 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between the first dark fringes on either side of the central bright fringe is
1.2 cm
1.2 mm
2.4 cm
2.4 mm
When light of wavelength 300 nm falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, light of wavelength 600 nm is sufficient for liberating photoelectrons. The ratio of the work function of the two emitters is
1 : 2
2 : 1
4: 1
1: 4