Test 4 (completed)

Question 1

Define pressure

Answer 1

the force acting per unit area at right angles to a surface

Question 2

Pressure increases with depth. What about with density?

Answer 2

Increases

Question 3

A student carries out an experiment to determine the specific heat capacity of a metal. A cylinder of the metal is heated by a 12W electrical heater.

State the readings that the student takes.

Answer 3

time, mass, initial and final temperature

Question 4

State the name for the defect of vision that can be corrected by a converging lens.

Answer 4

Long-sightedness

Question 5

State the name for the defect of vision that can be corrected by a diverging lens.

Answer 5

Short-sightedness

Question 6

Describe how a converging lens corrects long-sightedness.
You may find it helpful to sketch a ray diagram.

Answer 6

Without lens, rays converge behind of back of the eye. With, rays converge at the back of the eye, focusing the image on the retina. Reduces focal length of combined lens.

Question 7

State the type of electromagnetic radiation, other than visible light, which is used in glass optical fibres.

Answer 7

Infrared

Question 8

Give two reasons why these two types of electromagnetic radiation are used in glass optical fibres for high-speed broadband.

Answer 8

Glass is transparent to visible light and some infrared. Can carry high rates of data.

Question 9

An electric heater uses a resistance wire of resistance 26Ω. The power dissipated in the resistance
wire is 2500W. Calculate the current in the resistance wire.

Answer 9

P=I^2R

Question 10

The resistance wire of the heater has a length of 1.2m and a cross-sectional area of
7.9 × 10–7m2.

A new heater is designed using wire of the same material with length 1.8m and cross-
sectional area 5.8 × 10–7m2.

Calculate the resistance of this wire.

Answer 10

R=L/A
First one on top.

Question 11

What to remember with triangle diagrams?

Answer 11

head to tail
river current and bank

Question 12

What to remember with Fleming’s left and right hand rules

Answer 12

field

Question 13

During β-decay, one of the neutrons in the nucleus changes. Explain how charge is conserved during this change.

Answer 13

charge on neutron = 0 OR total charge on products = 0

charge on proton = +1 AND charge on electron =
–1

Question 14

(Planets)
Greater field=

Answer 14

larger mass and less dense