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- Question
When one enters a dark room after being in bright light one is not able to see anything clearly for a while because
Options- A. the retina of the eye moves forward
- B. the retina of the eye moves backward
- C. the iris is unable to dilate the pupil immediately to be able to see things
- D. the eye has no power of accommodation
- Correct Answer
- the iris is unable to dilate the pupil immediately to be able to see things
ExplanationThe size of the pupil of the eye automatically adjusts itself according to the intensity of light passing through it;if the intensity is more , the size is less, if less, it is more. So in our case the pupil should dilate i.e, increase in size to be able to see in the dark . This switchover takes sometime. But here the entry into the dark room is immediate . So the eye has no time to adjust itself and hence is not able to see at all for a while.
- 1. Optical fiber works on the principle of
Options- A. Scattering
- B. interference
- C. total internal reflection
- D. refraction Discuss
- 2. At what temperature do the Fahrenheit and celcius scales give the same reading?
Options- A. 212 degrees
- B. 32 degreees
- C. -40 degreees
- D. 0 degreees Discuss
- 3. Which of the following has the highest frequency?
Options- A. Cosmic rays
- B. X-rays
- C. Radio waves
- D. Microwaves Discuss
- 4. The image of an object formed on the retina of the eye is
Options- A. virtual and upright
- B. virtual and inverted
- C. real and inverted
- D. Real and upright Discuss
- 5. Two bodies A and B are of same mass and same amount of heat is given to both of them. If the temperature of A increases more than that of B because of heat addition, then
Options- A. the specific heat capacity of A is more than that of B
- B. the specific heat capacity of A is less than that of B
- C. both A and B have the same specific heat capacity but A has greater thermal conductivity
- D. both A and B the same specific heat capacity but B has greater thermal conductivity Discuss
- 6. Quality of transmission depends upon
Options- A. Nature of signal only
- B. Nature of medium only
- C. Both (A) and (B)
- D. Neither A nor B Discuss
- 7. Carbon Arc lamps are commonly used in
Options- A. cinema projectors
- B. photography
- C. vehicles
- D. domestic lighting Discuss
- 8. Unit of solid angle is
Options- A. degree
- B. radian
- C. steradian
- D. radian second Discuss
- 9. Which of the following is a scalar quantity
Options- A. electric current
- B. electric field
- C. Acceleration
- D. linear momentum Discuss
- 10. Which of the following is the fastest communication channel?
Options- A. Microwave
- B. Optical fiber
- C. Radio wave
- D. All are operating at nearly the same propagation speed Discuss
Physics problems
Search Results
Correct Answer: total internal reflection
Correct Answer: -40 degreees
Explanation:
We want the temperature when F=C.
We know that,
So substituting C For F, we have C =
Therefore, C = -40.
Thus when C = -40, we have C = F
Correct Answer: Cosmic rays
Correct Answer: real and inverted
Explanation:
Although the image is inverted the mental interpretation of the effect on the retina is as though it is erect
Correct Answer: the specific heat capacity of A is less than that of B
Correct Answer: Both (and (B)
Explanation:
Quality of transmission is governed both by nature of signal and nature of communication channel/medium.
Correct Answer: cinema projectors
Correct Answer: steradian
Correct Answer: electric current
Explanation:
A Scalar quantity is a quantity that has only magnitude but no direction as like vector.
Here in the given options, electric current is the only one which is scalar.
Correct Answer: Microwave
Explanation:
A microwave is the fastest communication channel whereas Optical fiber is a way of transferring data not a way of communication.
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