- A$\oint B \cdot d l=\Sigma i$
- ✓$\oint H \cdot d l=\Sigma i$
- C$\oint B d l=\frac{\Sigma i}{\mu_{ o }}$
- D$\oint H d l=\mu_{ o } \Sigma i$
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Consider three converging lenses L1, L2 and L3 having identical geometrical construction. The index of refraction of L1 and L2 are $\mu_1$ and $\mu_2$ respectively. The upper half of the lens L3 has a refractive index $\mu_1$ and the lower half has $\mu_2$. A point object O is imaged at O1 by the lens L1 and at O2 by the lens L2 placed in same position. If L3 is placed at the same place:

The velocity factor of a transmission line x. If dielectric constant of the medium is 2.6, the value of x is
|
(a) 0.26 |
(b) 0.62 |
(c) 2.6 |
(d) 6.2 |
The time period of a bar magnet suspended horizontally in the earth's magnetic field and allowed to oscillate
| (a) Is directly proportional to the square root of its mass |
| (b) Is directly proportional to its pole strength |
| (c) Is inversely proportional to its magnetic moment |
| (d) Decreases if the length increases but pole strength remains same |
A photocell stops emission if it is maintained at 2V negative potential. The energy of most energetic photoelectron is
|
(a) 2eV |
(b) 2J |
(c) 2kJ |
(d) 2keV |
Two identical light sources S1 and S2 emit light of same wavelength l. These light rays will exhibit interference if
|
(a) Their phase differences remain constant |
|
(b) Their phases are distributed randomly |
|
(c) Their light intensities remain constant |
|
(d) Their light intensities change randomly |
The mutual inductance between two coils is 1.25 henry. If the current in the primary changes at the rate of 80 ampere/second, then the induced e.m.f. in the secondary is
|
(a) 12.5 V |
(b) 64.0 V |
(c) 0.016 V |
(d) 100.0 V |
Certain radio-active substance reduces to 25% of its value in 16 days. Its half-life is
|
(a) 32 days |
(b) 8 days |
(c) 64 days |
(d) 28 days |
A parallel plate air capacitor is charged to a potential difference of V. After disconnecting the battery, distance between the plates of the capacitor is increased using an insulating handle. As a result, the potential difference between the plates
|
(a) Decreases |
(b) Increases |
(c) Becomes zero |
(d) Does not change |