The power of the lens is +2.5D. What is the radius of the curvature?
2.5 cm
25.0 cm
40.0 cm
80.0 cm
Correct answer is D
The power of a lens is defined as the reciprocal of its focal length in metres:
P = \(\frac{100}{f}\) → 2.5 = \(\frac{100}{f}\)
where P is the power in diopters and f is the focal length in metres.
2.5 * f = 100
f = \(\frac{100}{2.5}\)
f = 40
Where f = \(\frac{r}{2}\)
radius of the curvature[r] = f * 2 → 40 * 2
r = 80cm
doppler effect
beat
interference
resonance
Correct answer is B
beat, in physics, the pulsation caused by the combination of two waves of slightly different frequencies
u = 15cm only
u = 30cm only
M < 15cm only
u > 30cm only
Correct answer is D
Objects at a distance greater than two times of the focal length produces a real image, inverted and diminished in size.
→ 2 * 15 = 30cm
: At >30cm this is applicable
A freely suspended compass needle on the earth's surface settles in a plane called----------
geographic meridian
magnetic meridian
magnetic declination
isoganals
Correct answer is B
The magnetic meridian is an equivalent imaginary line connecting the magnetic south and north poles and can be taken as the horizontal component of magnetic force lines along the surface of the earth. Therefore, a compass needle will be parallel to the magnetic meridian
20N
25N
40N
100N
Correct answer is C
VR = 5:1 or 5
Load = 20kg or 200N
MA = \(\frac{200}{E}\)
Efficiency% = \(\frac{MA}{VR} * 100\)
100% = \(\frac{200}{5E} * 100\)
5E = 200
E = 40