Deck 6 = General information test

Question 1

The graph shows the current through a filament lamp change as the voltage increases, explain why the graph is not a straight line? (4)

Answer 1

• Increased voltage leads to higher current.
• Current has a heating effect in the filament / electrical energy transferred to thermal.
• Temperature (of filament) increases.
• Resistance (of filament) increases.
• Changing resistance illustrated by changing gradient of line.

Question 2

Besides reducing drag, why is it important for the main body of the car to be closer to the ground?

Answer 2

-Center of mass is lower.

Question 3

Use ideas about energy to explain why a car leaving the track at high speed rapidly decelerates through the gravel? (3)

Answer 3

• High speed means high KE.

- Car’s KE transferred/lost to gravel into KE of gravel (grains).

Question 4

As the rope stretches the bungee jumper slows, describe fully the energy transfer that happens as the bungee jumper continues to fall towards the ground? (3)

Answer 4

• KE of jumper transfers to the rope.
• GPE of jumper transfers to the rope.
• potential elastic energy (in rope).

Question 5

Suggest why doing two loads of washing at the economy setting would be less efficient than doing one full load? (2)

Answer 5

• Washing for greater/double time.

- More (heat) energy lost to surroundings/ machine.

Question 6

One way of reducing the heat transfer by droughts?

Answer 6

-Draught excluders/door seals.

Question 7

Explain how the air cavity between the two walls reduces the heat transfer from the house?

Answer 7

• Air is a poor conductor/good insulator.

- Reduces heat transfer by conduction.

Question 8

How can you tell that the filament lamp is hotter? (1)

Answer 8

-Link infrared to heat radiation/energy.

Question 9

How can you tell that the fluorescent lamp is more efficient at lighting the home? (2)

Answer 9

• All/more power output in visible spectrum.

- Visible light is the useful output energy/power.

Question 10

Explain why the acceleration of the athlete decreases to zero during the race? (2)

Answer 10

• Reaches Terminal Velocity.

- Driving force balanced by friction.

Question 11

Write down the equation that links current, voltage and resistance?

Answer 11

-V=IR.

Question 12

Describe how sound travels through the air and how it effects the eardrum? (2)

Answer 12

• Longitudinal wave or oscillations (of air particles) parallel to wave direction.
• Transfers energy to the eardrum.

Question 13

If the same experiment is carried out on Earth, air Resistance affects both objects. The feather reaches the ground after the hammer, even though the force of air resistance is smaller on the feather than on the hammer. Explain why the feather reaches the ground after the hammer?

Answer 13

• Feather has lower mass/weight than hammer.
• Lower air resistance required to balance weight.
• Feather’s terminal velocity lower.
• Takes more time to reach the ground.

Question 14

The family uses carpets and underlay to reduce the energy loss. Explain why this reduces heat loss?

Answer 14

• Contain trapped air.

- Air is a poor conductor / good insulator.

Question 15

Use your own knowledge of forces to explain what is meant by terminal velocity? (2)

Answer 15

• Constant velocity.

- When driving force is balanced by friction / Weight balanced by air resistance.

Question 16

When Jan opens her parachute her terminal velocity changes. Describe what happens to each of the two forces acting on her and how this causes change to her terminal velocity? (4)

Answer 16

• Weight remains the same.
• Air resistance increase (because of larger surface area).
• Resultant force (upwards).
• Deceleration until.
• Weight balanced by air resistance.
• Lower terminal velocity.

Question 17

A duck is in the bath. The water now drains out of the bath. The ripples become further apart. Peter thinks this is to do with the water getting shallower. Mary thinks it is because the clockwork is running down. Comment on these views as fully as you can. (3)

Answer 17

-Shallower water would decrease speed of wave.
-Therefore, wavelength would decrease (as v = fλ).
-Clockwork running down leads to lower f
Therefore, λ increases.

Question 18

Which measuring cylinder would give the most precise measurement? Explain your answer? (2)

Answer 18

• A

- Capable of recording the smallest value / to the nearest -0.2ml

Question 19

The most precise measuring cylinder may not give an accurate reading, suggest why? (1)

Answer 19

• Some water may already be in the cylinder.
• Surface may not be horizontal.
• Narrow tube hard to pour water into so spillage may occur.

Question 20

State two conditions required for total internal reflection to take place? (2)

Answer 20

1. Angle of incidence must be greater than the critical angle.
2. Fiber must have a greater refractive index than surrounding medium.

Question 21

Suggest one advantage of sending signals through optical fibers? (1)

Answer 21

-Signal faster / travels at the speed of light.

Question 22

Use ideas about particles to explain how a gas causes a pressure on the inside of a container? (3)

Answer 22

• (Gas particles have) high speed in random directions.
• Collisions exert a force on the inside of the container.
• Pressure = F/A.