Ray Optics and Optical Instruments - Online Test

Q1. An observer looks at a tree of height 15 metre with a telescope of magnifying power 10. To him, the tree appears
Answer : Option B
Explaination / Solution:
No Explaination.


Q2. The magnifying power of the telescope can be increased by
Answer : Option B
Explaination / Solution:
No Explaination.


Q3. The largest telescope in the world has a reflector with an aperture of 200 inches in order to achieve
Answer : Option B
Explaination / Solution:
No Explaination.


Q4. How will the image formed by a convex lens be affected if the central portion of the lens is wrapped in a black paper
Answer : Option B
Explaination / Solution:
No Explaination.


Q5. A bird flies down vertically towards a water surface. To a fish inside the water, vertically below the bird, the bird will appear to
Answer : Option A
Explaination / Solution:
No Explaination.


Q6. The layered lens is made of two kinds of glass. A point source of light is placed on its principal axis. If the reflections from the boundaries between layers are ignored, the lens will form
Answer : Option A
Explaination / Solution:
No Explaination.


Q7. Spherical aberration in a thin lens can be reduced by
Answer : Option B
Explaination / Solution:
No Explaination.


Q8. In a Young’s double-slit experiment, if the slits are of unequal width
Answer : Option C
Explaination / Solution:
No Explaination.


Q9. An equi-convex crown glass lens has a focal length 20 cm for violet rays. Its focal length for red rays is 
Answer : Option D
Explaination / Solution:
No Explaination.


Q10. A convex crown glass lens ( = 1.5 ) has a focal length of 8 cm when placed in air. What is the focal length of the lens when it is immersed in water  w
Answer : Option B
Explaination / Solution:
No Explaination.