- ACopper
- ✓Silicon
- CAluminium
- DNichrome
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A point object O is placed on the principal axis of a convex lens of focal length 20 cm at a distance of 40 cm to the left of it. The diameter of the lens is 10 cm. If the eye is placed 60 cm to the right of the lens at a distance h below the principal axis, then the maximum value of h to see the image will be
|
(a) 0 |
(b) 5 cm |
(c) 2.5 cm |
(d) 10 cm |
Which of the following spectral series in hydrogen atom give spectral line of 4860 Å
|
(a) Lyman |
(b) Balmer |
(c) Paschen |
(d) Brackett |
The velocity of photon is proportional to (where n is frequency)
|
(a) |
(b) |
(c) |
(d) n |
A thin plano-convex lens acts like a concave mirror of focal length 0.2 m when silvered from its plane surface. The refractive index of the material of the lens is 1.5. The radius of curvature of the convex surface of the lens will be
|
(a) 0.4 m |
(b) 0.2 m |
(c) 0.1 m |
(d) 0.75 m |
The temperature coefficient of resistance of a semiconductor
|
(a) Is always positive |
(b) Is always negative |
|
(c) Is zero |
(d) May be positive or negative or zero |
Which of the following relation is correct in magnetism
|
(a) |
(b) I = V + H |
(c) |
(d) |