An astronomical telescope is said to be in normal adjustment when the?
eye is accommodated
focal length of an object lens is longer than that of eye piece
final image is at the near point of eye
final image is at infinity
Correct answer is D
A normal arrangement is an arrangement where the principal focus of objective coincides with the eyepiece so that the final image is at infinity
0.33
0.50
0.67
0.75
Correct answer is D
\(\frac{\text {sin i}}{\text {sin r}}\) = \(\frac{\text {velocity in air}}{\text {velocity in glass}}\)
\(\frac{\text {sin i}}{\text {sin 30}}\) = \(\frac{3 \times 10^{8}}{2 \times 10^{8}}\)
Sin i = \(\frac{3}{4}\) = 0.75
concave mirror of focal length 5cm
concave mirror of focal length 10cm
convex mirror of focal length 5cm
convex mirror of focal length 10cm
Correct answer is C
Concave Mirror: It is a spherical mirror whose outer surface is polished and inner or concave side is reflecting surface.
Convex Mirror: It is a spherical mirror whose inner surface is polished and outer side or convex side is the reflecting surface.
f = \(\frac{m}{4}\) = f = \(\frac{d}{4}\)
f = \(\frac{20}{4}\) = 5cm
3m
5m
6m
10m
Correct answer is C
Objects distance (u) = image distance (v)
object distance = 3m
|uv| = 3 + 3 = 6m
4
3
2
1
Correct answer is B
f\(_{0}\) = 40H\(_{3}\)
1st overtone = 2f\(_{0}\) = 80H\(_{3}\)
2nd overtone = 3f\(_{0}\) = 120H\(_{3}\)
3rd overtone = 4f\(_{0}\) = 160H\(_{3}\)
4th overtone = 5f\(_{0}\) = 200H\(_{3}\)
\(\therefore\) Number of overtones between 40H\(_{3}\) and 180H\(_{3}\) = 3