Q: A proton and an electron are placed 1.0 cm apart in vacuum. What is the magnitude of the electric force between them? (Given: $$k = 8.99 \times 10^9$\ \text{N} \cdot \text{m}^2/\text{C}^2$$, $$e = 1.60 \times 10$$^{-19}$$\ \text{C})$$

$$2.3 \times 10$$^{-24}$$\ \text{N}$$

Question 1

A proton and an electron are placed 1.0 cm apart in vacuum. What is the magnitude of the electric force between them? (Given: $$k = 8.99 	imes 10^9$\ 	ext{N} \cdot 	ext{m}^2/	ext{C}^2$$, $$e = 1.60 	imes 10$$^{-19}$$\ 	ext{C})$$

Accepted Answer

$$2.3 	imes 10$$^{-24}$$\ 	ext{N}$$

Question 2

Which of the following statements about electric fields is correct?

Accepted Answer

The electric field at a point is the force per unit positive charge placed at that point.

Question 3

A 12 V battery is connected to a resistor of $$4\ \Omega. $$What is the power dissipated by the resistor?

Accepted Answer

$$36\ 	ext{W}$$

Question 4

Three identical light bulbs are connected in parallel to a battery. If one bulb burns out, what happens to the brightness of the remaining bulbs?

Accepted Answer

The brightness of the remaining bulbs stays the same.

Question 5

A wire carries a current of $$2\ 	ext{A}$$ perpendicular to a magnetic field of $$0.5\ 	ext{T}. $$What is the force on a $$0.3\ 	ext{m}$$ length of the wire?

Accepted Answer

$$0.6\ 	ext{N}$$

Question 6

A charged particle moves parallel to a uniform magnetic field. What is the magnetic force acting on it?

Accepted Answer

Zero

Question 7

A sound wave travels from air into water. Which of the following quantities remains unchanged?

Accepted Answer

Frequency

Question 8

A string fixed at both ends vibrates in its third harmonic. If the string is $$1.2\ 	ext{m}$$ long and the wave speed is $$180\ 	ext{m/s}$$, what is the frequency?

Accepted Answer

$$225\ 	ext{Hz}$$

Question 9

A police car approaches you with its siren on. Compared to the actual frequency emitted, what do you hear?

Accepted Answer

A higher frequency

Question 10

Light passes from glass ($$n=1.5) $$into air ($$n=1.0). $$What is the critical angle for total internal reflection?

Accepted Answer

$$41.8^\circ$$

Question 11

A double-slit experiment uses light of wavelength $$600\ 	ext{nm}$$, slit separation $$0.2\ 	ext{mm}$$, and screen distance $$2.0\ 	ext{m}. $$What is the distance between adjacent bright fringes?

Accepted Answer

$$3.0\ 	ext{mm}$$

Question 12

In a single-slit diffraction experiment, what happens to the width of the central maximum if the slit width is halved?

Accepted Answer

It doubles

Question 13

Which of the following best describes the change in light as it passes from air into water?

Accepted Answer

Speed decreases, wavelength decreases, frequency remains the same

Question 14

A nucleus has a mass defect of $$0.02\ 	ext{u}. $$What is its binding energy in MeV?

Accepted Answer

$$18.62\ 	ext{MeV}$$

Question 15

A radioactive sample has a half-life of 3 hours. What fraction of the original nuclei remains after 9 hours?

Accepted Answer

$$\frac{1}{8}$$

Question 16

Which process releases energy by combining light nuclei?

Accepted Answer

Fusion

Question 17

A hospital uses a radioactive isotope with a decay constant $$k = 0.231\ 	ext{hr}^{-1}. If $$the initial activity is $$1000\ 	ext{Bq}$$, what is the activity after 6 hours?

Accepted Answer

$$250\ 	ext{Bq}$$

Question 18

A student incorrectly calculates the electric potential at a point by using $$V = k \frac{q}{r^2$}$$ instead of the correct formula. What physical quantity did they actually calculate?

Accepted Answer

Electric field

Question 19

Which of the following is a common mistake when analyzing circuits with both series and parallel resistors?

Accepted Answer

Adding the reciprocals of resistances in series

Question 20

A laser of wavelength $$500\ 	ext{nm}$$ passes through a single slit of width $$0.05\ 	ext{mm}$$ and projects onto a screen $$2.0\ 	ext{m}$$ away. What is the width of the central maximum?

Accepted Answer

$$4.0\ 	ext{cm}$$

PCS130 Final Exam Master Review: Electrostatics, Circuits, Magnetism, Waves, Optics, and Nuclear Physics

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