OAT Physics Principles 3

Question 1

A 500 kg elevator accelerates upward at 2 m/s². What is the tension in the supporting cable? (g = 10 m/s²)

Accepted Answer

6000 N

Answer

T − mg = ma → T = m(g + a) = 500(10 + 2) = 6000 N.

Question 2

Which law states that the total electric flux through a closed surface equals the enclosed charge divided by the permittivity of free space?

Accepted Answer

Gauss's Law

Answer

Gauss's Law relates total electric flux through a closed (Gaussian) surface to the enclosed charge: Φ = Q_enc/ε₀.

Question 3

A convex lens has a focal length of 20 cm. An object is placed 30 cm from the lens. Where is the image formed?

Accepted Answer

60 cm on the opposite side

Answer

1/v − 1/u = 1/f → 1/v = 1/20 + 1/30 = 5/60 → v = 60 cm on the opposite side (real image).

Question 4

Which property of sound determines its perceived loudness?

Accepted Answer

Amplitude

Answer

Loudness is determined by amplitude (or intensity); greater amplitude causes greater pressure variation and louder sound.

Question 5

A battery of EMF 12 V and internal resistance 1 Ω is connected to a 5 Ω external resistor. What is the terminal voltage?

Accepted Answer

10 V

Answer

Current I = 12/(1+5) = 2 A; terminal voltage = EMF − Ir = 12 − 2(1) = 10 V.

OAT - Optometry Admission Test Practice Test