MCQ
The power factor of L-R circuit is :
- A$R+\omega L$
- ✓$R/\sqrt{(R^{2}+\omega^{2}L^{2})}$
- C$R.\sqrt{(R^{2}+\omega^{2}L^{2})}$
- D$\omega L/R$
✓
Answer
Correct option: B.
$R/\sqrt{(R^{2}+\omega^{2}L^{2})}$
B
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Ge and Si diodes conduct at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the valve of V0 changes by
|
(a) 0.2 V |
(b) 0.4 V |
(c) 0.6 V |
(d) 0.8 V |
Huygen's concept of wavelets is useful in:
Two infinitely long parallel conducting plates having surface charge densities +σ and -σ respectively, are separated by a small distance. The medium between the plates is vacuum. If 
is the dielectric permittivity of vacuum, then the electric field in the region between the plates is
|
(a) 0 volts/meter |
(b) |
(c) |
(d) |
The particle nature of light is not confirmed by:
A straight wire of length (
metre is carrying a current of 2A and the magnetic field due to it is measured at a point distant 1 cm from it. If the wire is to be bent into a circle and is to carry the same current as before, the ratio of the magnetic field at its centre to that obtained in the first case would be
|
(a) 50 : 1 |
(b) 1 : 50 |
(c) 100 : 1 |
(d) 1 : 100 |
Number of secondary electrons emitted per number of primary electrons depends on
|
(a) Material of target |
(b) Frequency of primary electrons |
|
(c) Intensity |
(d) None of the above |
Interference was observed in interference chamber when air was present, now the chamber is evacuated and if the same light is used, a careful observer will see
|
(a) No interference |
|
(b) Interference with bright bands |
|
(c) Interference with dark bands |
|
(d) Interference in which width of the fringe will be slightly increased |
The alternating voltage induced in the secondary coil of a transformer is mainly due to
|
(a) A varying electric field |
(b) A varying magnetic field |
|
(c) The vibrations of the primary coil |
(d) The iron core of the transformer |
A point source of light is placed at a distance, of 2f from a converging lens of focal length f. The intensity on the other side of the lens is maximum at a distance:
The rms speed of oxygen molecules in a gas is v. If the temperature is doubled and the oxygen molecules dissociate into oxygen atoms, the rms speed will become:
→- $\text{v}$
- $\text{v}\sqrt{2}$
- $2\text{v}$
- $4\text{v}$