PHYSICS P1 2020

What is meant by a zero error (1)

The instrument displays a reading when not in use/connected

Give two environmental advantages of using a gas-fired power station to generate electricity compared with using a coal-fired power station (2)

Any two from:

• no sulfur dioxide released

• doesn’t cause acid rain

• no particulates released

• doesn’t cause global dimming

• less carbon dioxide released (per kg of fuel burned)

• less global warming

• no solid waste

• gas mining is less destructive than coal mining

thermistor c

• because change in resistance is greatest

• between 0 and 25^oC

Nuclear fission releases energy

Describe the process of nuclear fission inside a nuclear reactor (4)

• neutron absorbed by a uranium nucleus

• nucleus splits into two (roughly identical smaller nuclei)

• and neutrons are released

• gamma rays are emitted

• (energy released by fission reaction)

Explain how the process of nuclear fusion leads to the release of energy (2)

• lighter nuclei join to form heavier nuclei

• some of the mass is converted to energy

Explain the advantage of radioactive waste having a shorter half-life (2)

• activity decreases quickly

• risk of harm decreases quickly

• length of sled

• time for sled to pass light gate

At the bottom of the slide, all riders and their sleds have approximately the same speed

Explain why (4)

• 0.5mv² = mgh or decrease in gpe = increase in Ek

• masses cancel on both sides of the equation or v² = 2gh

• final speed only depends on vertical height (ang gravitational field strength) (which is the same for all riders)

• variations will be due to air resistance/friction

When a kettle was switched on, the temp did not immediately start to increase

Suggest one reason why (1)

the heating element of the kettle takes time to heat up / kettle takes time to heat up

How to show a graph is inversely proportional for three marks

• three pairs of values showing that the x (value) * y (value) = constant

→ three different pairs of values multiply to same thign

• write statement: e.g. so (whatever is measured on x axis) * (whatever is measured on y axis) = constant

Explain why adding resistors in parallel decreases the total resistance (2)

• multiple paths for charge to flow

• total current is greater

An electrician replaced the switch. The electrician would have received an electric shock unless the circuit was disconnected from the mains supply.

Explain why. (3)

• one wire in the switch is live

• the electrician is earthed

• so there will be a large p.d between the live wire and electrician

Explain why temperature increase gas pressure in a balloon (4)

• particles have higher kinetic energy

• so increased number of collisions with walls of balloon per second/ more frequent collisions with walls of balloon

• greater forces exerted in collisions

• greater force exerted on same area, means pressure increases