Which of the following prefix represents 10⁻¹⁵? MCQ with Answer and Explanation

Which of the following prefix represents 10⁻¹⁵?
A. Femto
B. Pico
C. Nano
D. Atto
Answer: Option A
Solution (By JKSSB Mock Tests)
Femto (f) = 10⁻¹⁵. Pico (p) = 10⁻¹², nano (n) = 10⁻⁹, atto (a) = 10⁻¹⁸. The prefix chain: milli 10⁻³, micro 10⁻⁶, nano 10⁻⁹, pico 10⁻¹², femto 10⁻¹⁵, atto 10⁻¹⁸. Mnemonic: Femto is 'fifteen'.

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Practice More Physics Questions

Question #1
Newton's second law gives the measure of
A. Momentum
B. Energy
C. Inertia
D. Force

Correct Answer: Option D


Explanation:
F = ma, defines force quantitatively. First law inertia, third action-reaction.

This question belongs to: Science Physics
Question #2
Identify the incorrect statement regarding the human eye.
A. The cornea provides most of the eye's refractive power.
B. The pupil regulates the amount of light entering the eye.
C. The image formed on the retina is virtual and erect.
D. The retina acts as the screen where images are formed.

Correct Answer: Option C


Explanation:
The eye lens is a convex (converging) lens. It converges light rays to form a real and inverted image on the retina. The brain processes this signal and flips it so we perceive the world as erect. All other statements are functionally correct. The cornea does indeed do about two-thirds of the focusing.

This question belongs to: Science Physics
Question #3
A ray of light travels from glass (μ=1.5) to air. Critical angle is
A. sin⁻¹(1.5)
B. sin⁻¹(2/3)
C. sin⁻¹(1/1.5)
D. sin⁻¹(1/3)

Correct Answer: Option C


Explanation:
sin C = 1/μ = 2/3 ≈ 0.6667, C = sin⁻¹(2/3). So option A: sin⁻¹(2/3). Wait sin C = n2/n1 = 1/1.5 = 2/3. So C = sin⁻¹(2/3). Option A is sin⁻¹(2/3). I'll correct to A.

This question belongs to: Science Physics