1
KCET 2018
MCQ (Single Correct Answer)
+1
-0
The number of photons falling per second on a completely darkened plate to produce a force of $6.62 \times 10^{-5} \mathrm{~N}$ is $n$. If the wavelength of the light falling is $5 \times 10^{-7} \mathrm{~m}$, then $n=$ $\ldots \ldots \ldots \times 10^{22}$. (Take, $h=6.62 \times 10^{-34} \mathrm{~J}-\mathrm{s}$ )
A
1
B
5
C
0.2
D
3.3
2
KCET 2018
MCQ (Single Correct Answer)
+1
-0
An object is placed at the principal focus of a convex mirror. The image will be at
A
centre of curvature
B
principal focus
C
infinity
D
no image will be formed
3
KCET 2018
MCQ (Single Correct Answer)
+1
-0
An object is placed at a distance of 20 cm from the pole of a concave mirror of focal length 10 cm . The distance of the image formed is
A
+20 cm
B
+10 cm
C
-20 cm
D
-10 cm
4
KCET 2018
MCQ (Single Correct Answer)
+1
-0
A candle placed 25 cm from a lens forms an image on a screen placed 75 cm on the other side of the lens. The focal length and type of the lens should be
A
+18.75 cm and convex lens
B
-18.75 cm and concave lens
C
+20.25 cm and convex lens
D
-20.25 cm and convex lens