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WorksheetsPeriodic test trial
Total questions: 10
Worksheet time: 6mins
A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen.
half the image will disappear.
incomplete image will be formed.
intensity of image will decrease but complete image is formed.
intensity of image will increase but image is not distinct.
In optical fibres, the refractive index of the core is
greater than that of the cladding.
equal to that of the cladding.
smaller than that of the cladding.
independent of that of cladding.
We combine two lenses, one is convex and other is concave having focal lengths f1, and f2 and their combined focal length is F. Combination of the lenses will behave like concave lens, if
f1 > f2
f1 = f2
f1 < f2.
f1 ≤ f2
The length of an astronomical telescope for normal vision (relaxed eye) will be
fo - fe
fo + fe
fo x fe
fo / fe
The focal length of a biconvex lens of radii of each surface 50 cm and refractive index 1.5, is
40.4 cm
75 cm
50 cm
80 cm
A metal coin is at bottom of a beaker filled with a liquid of refractive index = 4/3 to height of 6 cm. To an observer looking from above the surface of liquid, coin will appear at a depth
1.5 cm
6.75 cm
4.5 cm
7.5 cm
. If a convex lens of focal length 80 cm and a concave lens of focal length 50 cm are combined together, what will be their resulting power?
+ 6.5 D
– 6.5 D
+ 7.5 D
– 0.75 D
. The refractive index of the material of an equilateral prism is √3. What is the angle of minimum deviation?
45°
60°
37°
30°
When a ray of light enters from one medium to another, then which of the following does not change?
Frequency
Wavelength
Speed
Amplitude
The optical density of turpentine is higher than that of water while its mass density is lower. Figure shows a layer of turpentine floating over water in a container. For which one of the four rays incident on turpentine in figure the path shown is correct?
1
2
3
4
