Which of the following colours has the longest wavelength? MCQ with Answer and Explanation

Which of the following colours has the longest wavelength?
A. Red
B. Green
C. Blue
D. Violet
Answer: Option A
Solution (By JKSSB Mock Tests)
Visible spectrum: red ~700 nm, orange, yellow, green, blue, indigo, violet ~400 nm. Red has longest wavelength, lowest frequency. Violet shortest wavelength, highest frequency. Remember VIBGYOR.

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Practice More Physics Questions

Question #1
A 5 Ω resistor dissipates 20 W power. Current through it is
A. 4 A
B. 2 A
C. 100 A
D. 0.5 A

Correct Answer: Option B


Explanation:
P = I² R => I = √(P/R) = √(20/5) = √4 = 2 A.

This question belongs to: Science Physics
Question #2
C.V. Raman discovered the Raman effect in which year?
A. 1905
B. 1913
C. 1928
D. 1930

Correct Answer: Option C


Explanation:
Raman effect discovered in 1928, Nobel in 1930.

This question belongs to: Science Physics
Question #3
The centre of mass of a uniform semicircular ring of radius R lies at distance from centre
A. R/π
B. R/2
C. 2R/π
D. R/3

Correct Answer: Option C


Explanation:
For semicircular ring, y_cm = 2R/π from centre.

This question belongs to: Science Physics