OAT OAT: Physics Principles Questions and Answers

Question 1

A ray of light travels from air (n ≈ 1.00) into a block of glass (n ≈ 1.50). Which of the following best describes the behavior of the light ray as it enters the glass?

Accepted Answer

It bends toward the normal.

Answer

According to Snell's Law (n₁sinθ₁ = n₂sinθ₂), when light enters a medium with a higher index of refraction (n₂ > n₁), the angle of refraction (θ₂) must be smaller than the angle of incidence (θ₁) to maintain the equality. A smaller angle relative to the normal means the ray bends toward the normal.

Question 2

A projectile is launched from the ground with an initial velocity at an angle above the horizontal. Neglecting air resistance, what is the vertical component of its velocity at the highest point of its trajectory?

Accepted Answer

0 m/s

Answer

At the highest point of its trajectory, a projectile momentarily stops moving upward before it begins to fall back down. Therefore, its vertical velocity is instantaneously zero. The horizontal component of velocity remains constant throughout the flight (in the absence of air resistance), but the question specifically asks for the vertical component.

Question 3

A resistor in a circuit has a resistance of 20 Ω and a current of 0.5 A flowing through it. What is the voltage drop across the resistor and the power it dissipates?

Accepted Answer

10 V, 5 W

Answer

The voltage drop (V) is calculated using Ohm's Law: V = IR. So, V = (0.5 A) * (20 Ω) = 10 V. The power dissipated (P) is calculated using the formula P = IV. So, P = (0.5 A) * (10 V) = 5 W. Alternatively, power can be calculated as P = I²R = (0.5 A)² * (20 Ω) = (0.25 A²) * (20 Ω) = 5 W.

Question 4

Which of the following correctly ranks the given types of electromagnetic radiation from longest wavelength to shortest wavelength?

Accepted Answer

Radio waves, Infrared, Visible light, X-rays

Answer

The electromagnetic spectrum is ordered by wavelength (or frequency/energy). Radio waves have the longest wavelengths, followed by microwaves, infrared, visible light, ultraviolet, X-rays, and finally gamma rays with the shortest wavelengths. Therefore, the correct sequence from longest to shortest is Radio waves, Infrared, Visible light, X-rays.

Question 5

In a thermodynamic process, 500 J of heat is added to a system, and the system performs 200 J of work on its surroundings. What is the change in the internal energy of the system?

Accepted Answer

300 J

Answer

The First Law of Thermodynamics states that the change in a system's internal energy (ΔU) is equal to the heat (Q) added to the system minus the work (W) done by the system. The convention is: Q is positive when heat is added, and W is positive when work is done by the system. Therefore, ΔU = Q - W = 500 J - 200 J = 300 J. The internal energy increases.

OAT - Optometry Admission Test Practice Test

OAT - Optometry Admission Test Practice Test

OAT OAT: Physics Principles Questions and Answers