Question 1

Why is it fundamentally impossible to resolve individual atoms using visible light in an optical microscope?

Accepted Answer

Because the wavelength of visible light is much larger than the size of an atom, causing significant diffraction and blurring.

Question 2

A 1-mm cube is scaled up by a factor of 5 in all dimensions. What is the new surface area of the cube?

Accepted Answer

$$150\ \mathrm{mm}^2$$

Question 3

A 200 N weight stretches a spring by $$10\ \mathrm{cm}$$ from its natural length of $$1\ \mathrm{m}. If a 400 N $$weight is hung from the same spring, what is the new length of the spring?

Accepted Answer

$$1.2\ \mathrm{m}$$

Question 4

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 5

A block has a mass of $$600\ \mathrm{g}$$ and a density of $$3000\ \mathrm{kg}/\mathrm{m}^3. $$What is its volume?

Accepted Answer

$$200\ \mathrm{cm}^3$$

Question 6

A dam is constructed with a thicker base than top. What is the main reason for this design?

Accepted Answer

Water pressure increases with depth, so the base must withstand greater pressure.

Question 7

A balloon expands to four times its original volume. What happens to its density?

Accepted Answer

Its density decreases by a factor of 4.

Question 8

Which of the following best explains why glass is a good electrical insulator?

Accepted Answer

Its outer electrons are tightly bound to the atoms, preventing free movement of charge.

Question 9

A ping-pong ball bobs up and down 6 times in 3 seconds as a wave of wavelength $$5\ \mathrm{m}$$ passes by. What is the speed of the wave?

Accepted Answer

$$10\ \mathrm{m/s}$$

Question 10

A heat engine absorbs $$500\ \mathrm{J} of $$heat and does $$200\ \mathrm{J} of $$mechanical work. What is the change in internal energy of the system?

Accepted Answer

$$300\ \mathrm{J}$$

Question 11

Which of the following is necessary to cook a potato faster in a covered saucepan?

Accepted Answer

Both a higher boiling point and higher pressure inside the saucepan.

Question 12

Which of the following best describes an adiabatic system?

Accepted Answer

A system that does not exchange heat with its surroundings.

Question 13

Which of the following is the most responsible factor in determining the phase (solid, liquid, gas) of a substance?

Accepted Answer

Temperature

Question 14

Which of the following statements about the greenhouse effect is correct?

Accepted Answer

Low frequency infrared waves are blocked by the greenhouse effect.

Question 15

Which of the following is true about the Doppler effect for sound?

Accepted Answer

It does not occur when neither the source nor the observer is moving toward or away from each other.

Question 16

Which of the following is a property shared by both P-waves and S-waves?

Accepted Answer

Frequency, speed, and wavelength

Question 17

When a load is placed on the middle of a horizontal beam supported at each end, what happens to the top part of the beam?

Accepted Answer

It undergoes compression.

Question 18

Which of the following best explains why evaporation is a cooling process?

Accepted Answer

Highly energetic molecules escape from the liquid surface, lowering the average kinetic energy.

Question 19

Which of the following processes require a medium to transfer heat?

Accepted Answer

Both conduction and convection.

Question 20

Which of the following best describes the second law of thermodynamics?

Accepted Answer

Heat does not flow from cold to hot without external energy.

Step-by-Step Guidance for Physics Practice Exam #2

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