The pin-hole camera produces a less sharply defined image when the
pin-hole is larger
illumination is less
screen is further from the pin-hole
object is further from the pin-hole
Correct answer is A
- a less sharp or blurred image is due to increased brightness
- increase brightness is also due to large hole or many pin holes
180\(^o\)
90\(^o\)
0\(^o\)
60\(^o\)
Correct answer is C
- a ray of light passing through the centre of a curvature is returned along the same path
- angle difference along the same path is zero
6.5 cm
7.5 cm
8.5 cm
4.5 cm
Correct answer is B
u + v = 40
\(\frac{v}{u}\) = 3
v = 3u
u + 3u = 40
4u = 40
u = 10cm
v = 3u = 30cm
f = \(\frac{uv}{u + v} = \frac{10(30)}{10 + 30} = \frac{300}{40}\)
= 7.5 cm
When the temperature of a liquid is increased, its surface tension?
increases
decreases
remain constant
increases then decreases
Correct answer is B
Surface tension or elasticity of a fluid decreases with increased temperature
Ripple in a power supply unit is caused by
using an alternating current source
forward voltage drop
heavy load
using a zener diode
Correct answer is A
The fluctuation of d.c signal results from the rectification of A.C source to d.c.