Concepts Of Physics MCQ Edition [Volume 1]
- Exam
- Concepts Of Physics MCQ Edition [Volume 1]
- Subject
- Physics
- Chapter
- Speed of Light
Concepts Of Physics MCQ Edition [Volume 1] · Physics · Speed of Light
For an experiment using Foucault's apparatus, the setup distances...
For an experiment using Foucault's apparatus, the setup distances are given as follows:
Distance between the rotating and the fixed mirror ,
Distance between the lens and the rotating mirror ,
Distance between the source and the lens .
Upon rotating the mirror at a speed of revolutions per second, a shift of is observed in the image. Determine the speed of light from this data.
Distance between the rotating and the fixed mirror ,
Distance between the lens and the rotating mirror ,
Distance between the source and the lens .
Upon rotating the mirror at a speed of revolutions per second, a shift of is observed in the image. Determine the speed of light from this data.
Options
- A
- B
- C
- D
Correct answer
B.
Step-by-step solution
In Foucault's rotating mirror experiment, the shift in the image is given by the formula:
where:
= distance between the rotating and fixed mirror =
= distance between the lens and the rotating mirror =
= distance between the source and the lens =
= angular velocity of the rotating mirror =
= frequency of rotation =
= shift in the image =
= speed of light
Rearranging the formula to solve for the speed of light :
Substituting the given values and using :
Canceling from the numerator and denominator:
Rounding to two decimal places, we get .
Answer:
where:
= distance between the rotating and fixed mirror =
= distance between the lens and the rotating mirror =
= distance between the source and the lens =
= angular velocity of the rotating mirror =
= frequency of rotation =
= shift in the image =
= speed of light
Rearranging the formula to solve for the speed of light :
Substituting the given values and using :
Canceling from the numerator and denominator:
Rounding to two decimal places, we get .
Answer: