Cuestionario: Fundamentals of Physics and Nuclear Science — 8 preguntas

1. Which equation gives the kinetic energy of a moving object in terms of its mass and speed?

A. GPE = mgh

B. E = Pt

C. rho = m/V

D. KE = 1/2 mv^2

Answer: (D)

Explicación

Kinetic energy depends on mass and the square of speed, so the correct equation is KE = 1/2 mv^2. The other equations describe gravitational potential energy, electrical energy transfer, or density.

2. What is the efficiency of a device defined as?

A. Energy stored per unit height

B. Useful energy output divided by total energy input

C. Energy transferred per second

D. Total energy input divided by useful energy output

Answer: (B)

Explicación

Efficiency is the fraction of input energy that becomes useful output energy, so it is useful divided by total. The reversed ratio would not represent efficiency.

3. In a series circuit, how does the current behave through the components?

A. It splits equally between branches

B. It increases after each component

C. It is the same everywhere in the circuit

D. It is zero in the live wire

Answer: (C)

Explicación

A series circuit has one path, so the current is the same at every point. Splitting current is a feature of parallel circuits, not series circuits.

4. Which statement correctly describes UK mains electricity conductors?

A. Live is brown, neutral is green/yellow, and earth is blue

B. Live is blue, neutral is brown, and earth is red

C. Live is brown, neutral is blue, and earth is green/yellow

D. Live is green/yellow, neutral is blue, and earth is brown

Answer: (C)

Explicación

UK mains wiring uses brown for live, blue for neutral, and green/yellow for earth. The supply is also standardized at 230 V and 50 Hz.

5. How is density calculated?

A. Mass divided by volume

B. Force divided by area

C. Energy divided by time

D. Volume divided by mass

Answer: (A)

Explicación

Density is defined as mass per unit volume, so the correct equation is rho = m/V. The other expressions describe different physical quantities.

6. What relationship between pressure and volume applies to a gas at constant temperature?

A. KE = 1/2 mv^2

B. P1V1 = P2V2

C. V = IR

D. E = Pt

Answer: (B)

Explicación

For a fixed mass of gas at constant temperature, pressure and volume obey P1V1 = P2V2. This is the gas law used for compression and expansion questions.

7. What is an isotope?

A. Atoms that emit gamma radiation only

B. Atoms with different numbers of protons and the same neutrons

C. Atoms that have no neutrons in the nucleus

D. Atoms of the same element with the same protons but different neutrons

Answer: (D)

Explicación

Isotopes are atoms of the same element, so they have the same number of protons but different numbers of neutrons. Changing the proton number would make a different element.

8. Which statement best describes gamma radiation?

A. It is an electron that is stopped by aluminium

B. It is a helium nucleus that is stopped by paper

C. It is an electromagnetic wave that is the least ionising and is stopped by lead

D. It is a proton emitted from the nucleus

Answer: (C)

Explicación

Gamma radiation is electromagnetic, has the least ionising effect, and is stopped by lead. Alpha and beta radiation are particle emissions with different shielding properties.