The wavelength of visible light lies between MCQ with Answer and Explanation

The wavelength of visible light lies between
A. 400 nm - 700 nm
B. 700 nm - 1 mm
C. 1 nm - 10 nm
D. 1 mm - 10 mm
Answer: Option A
Solution (By JKExamLibrary)
Visible spectrum approx 400 nm (violet) to 700 nm (red).

This question belongs to: Science Physics

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Practice More Physics Questions

Question #1 Report Error
If a force of 10 N acts on a body and displaces it by 2 m in the direction of the force, the work done is:
A. 5 J
B. 20 J
C. 12 J
D. 0 J

Correct Answer: Option B


Explanation:
Work done (W) is calculated as the dot product of force and displacement: W = F × d × cos(θ). Since the displacement is in the direction of the force, the angle θ is 0°, and cos(0°) = 1. W = 10 N × 2 m × 1 = 20 Joules (J).

This question belongs to: Science Physics
Question #2 Report Error
According to Brewster's Law, when unpolarized light is incident on a transparent medium at the polarizing angle (Brewster's angle), the reflected and refracted rays are:
A. At 45 degrees to each other
B. Totally internally reflected
C. Parallel to each other
D. At exactly 90 degrees to each other

Correct Answer: Option D


Explanation:
Brewster's Law states that when light hits a dielectric boundary at a specific angle of incidence (Brewster's angle, theta_p), the reflected light is completely plane-polarized. At this exact geometric condition, the angle between the reflected ray and the refracted (transmitted) ray is strictly 90 degrees.

This question belongs to: Science Physics
Question #3 Report Error
A block of mass 10 kg is accelerating at 2 m/s^2 on a horizontal surface under an applied force of 50 N. What is the magnitude of the frictional force opposing its motion?
A. 30 N
B. 70 N
C. 20 N
D. 50 N

Correct Answer: Option A


Explanation:
According to Newton's Second Law, the net force on the block is F_net = mass * acceleration = 10 kg * 2 m/s^2 = 20 N. The net force is the difference between the applied forward force and the opposing frictional force (F_net = F_applied - F_friction). So, 20 N = 50 N - F_friction. Solving for friction gives F_friction = 50 - 20 = 30 N.

This question belongs to: Science Physics