When white light passes through a glass prism, it splits into a spectrum of seven colors. Which color deviates the least? MCQ with Answer and Explanation

When white light passes through a glass prism, it splits into a spectrum of seven colors. Which color deviates the least?
A. Violet
B. Red
C. Yellow
D. Blue
Answer: Option B
Solution (By JKExamLibrary)
Dispersion occurs because different colors of light travel at slightly different speeds inside the glass prism, meaning they have different refractive indices. Red light has the longest wavelength, the lowest refractive index in glass, and therefore deviates (bends) the least. Violet has the shortest wavelength and deviates the most.

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Question #1 Report Error
A train 150 m long running at 60 km/h crosses a man walking at 6 km/h in opposite direction. Time taken is
A. 15 s
B. 9 s
C. 12 s
D. 6 s

Correct Answer: Option B


Explanation:
Relative speed = 60+6 = 66 km/h = 66×5/18 = 55/3 m/s. Time = distance / relative speed = 150 / (55/3) = 450/55 = 8.18 s ≈ 9 s. Actually 450/55=8.18, nearest 9 s. Option B.

This question belongs to: Science Physics
Question #2 Report Error
The prefix 'Peta' in the SI system represents which power of 10?
A. 10^9
B. 10^18
C. 10^12
D. 10^15

Correct Answer: Option D


Explanation:
In the SI system of prefixes, 'Peta' stands for 10^15. Other common large prefixes include Kilo (10^3), Mega (10^6), Giga (10^9), Tera (10^12), and Exa (10^18). It's crucial to memorize both positive and negative powers (like nano, pico, femto) for competitive exams.

This question belongs to: Science Physics
Question #3 Report Error
Assertion (A): The acceleration due to gravity is less at the equator than at the poles. Reason (R): Earth's rotation causes a centrifugal effect that reduces effective gravity at the equator.
A. Both A and R are true, and R is the correct explanation of A
B. Both A and R are true, but R is not the correct explanation of A
C. A is true, but R is false
D. A is false, but R is true

Correct Answer: Option A


Explanation:
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This question belongs to: Science Physics