Physics Paper 1

Question 1

Energy Law

Answer 1

Energy is always conserved - It cannot be created or destroyed (but can be turned into mass). It is measured in Joules (J). An object can have energy in the following stores

Question 2

Specific Heat Capacity

Answer 2

Specific heat capacity. SHC (J/kg c): the energy needed to raise the temp of 1kg of a substance by 1C (e.g. 4200J/kg C for water)

Question 3

Energy Transfers

Answer 3

Things happen when objects interact (in what we call a system) and energy is transferred from one store to another, or between objects.

Question 4

Closed System

Answer 4

In a closed system, no energy is tranferred to or from the surroundings, so in this case we can sat KE= GPE, or KE= EPE.

Question 5

Specific Heat Capacity RP

Answer 5

Method:
-Measure mass of metal block or water in beaker, using top pan balence.
-Place electrical heater in metal block/water.
-Measure initial temperature of substance using thermometer
-Turn heater on, starart timer and measure p.d. and current supplied to heater using voltmeter and ammeter
-After set time, measure final temperature and calculate change in temperature (FINAL - INITIAL).

Question 6

Power And Efficiency

Answer 6

Efficiency is the proportional/ratio of TOTAL INPUT energy/power that is converted to USEFUL OUTPUT energy

Question 7

Fossil Fuels

Answer 7

Contribute to global warming and are being used faster than they are produces=running out e.g. Oil, Coal and natural gas.

Question 8

Renewable resources

Answer 8

These are energy sources that can be replaced e.g. Wind, Solar, Hydroelectric, Biofuels, Tidal, Wave.

Question 9

Electrical circuits

Answer 9

Energy is supplied to electrons by a cell/batter or mains elctricity which then move through the wires to transfer energy. Cells/batteries have a store of chemical potential energy.

Question 10

Potential difference

Answer 10

PD is the measure of how much energy is transferred to/by each COULOMB of electrons/charge Units= Volts (v).

Question 11

Current

Answer 11

Current is the rate of flow charge (how many Coulombs pass every second) Units= Amps/Amperes (A).

Question 12

Resistance

Answer 12

The measure of how much a component/object resists the flow of current Units= Ohms.

Question 13

Series Circuit

Answer 13

• Total p.d. is shared between all componets
• Current is the same for all components
• Total resistance= sum of resistances.

Question 14

Parallel Circuit

Answer 14

• p.d. for each branch= p.d. of cell/battery
• Current is split between the branches
• Adding more resistors in parrallel reduces the total R.

Question 15

Thermistor

Answer 15

Does the opposite to a metal/filament if temperature increases, resistance decreases.

Question 16

LDR (Light dependent resistor)

Answer 16

Simillar to thermistor but for light: if light intensity increases, resistance decreases.

Question 17

Mains electricity

Answer 17

A.C. Alternating current resulting from Alternating P.D. (both of these reverse direction at a frequency of 50Hz, at least in the UK)

Question 18

The Earth Wire

Answer 18

A safety feature: it acts as an escape route for currents that would otherwise cause a shock if the appliance is touched. Not needed for double insualted appliances.

Question 19

Plugs

Answer 19

Every plug has a fuse connected ot the live wire. Its a thin metal wire in a tube thats designed to melt or blow if there is a fault that causes a high current, usually 3A,5A,13A

Question 20

The National Grid Order

Answer 20

Power Station

Step-up transformer

National grid cables

Step-down transformer

Homes/businesses

Question 21

Static Electricity

Answer 21

If electroins are transferred between insulation material, they will remain charged - this is static electricity

Electrons are negatively charged, so if an object gains electrons it becomes Negatively Charged if it loses them it becomes Positively Charged

Opposite charges will ATTRACT while like charges will REPEL

Question 22

Density RP

Answer 22

1. Measure the mass first
2. fill displacement can up to spout
3. Using string, submerge object and wait for all water to be displaced out into beaker
4. Pour water into measuring cylinder to measure the volume USE MENISCUS

Question 23

Atomic Structure

Answer 23

Ancient Greeks thought matter to be made of indivisible particles

JJ Thompson Created the Plum Pudding model

Ernest Rutherford discovered that the nucleus was small and positively charged.

Neils Bohr deduced that electrons exist in shells or energy levels

James Chadwick determined that the nucleus must contain neutrons as well as protons

Question 24

Periodic table Numbers on atom

Answer 24

Mass number is the top number which is the number of protons and neutrons

The Atomic number, the bottom
one, is the number of protons

Question 25

Isotopes

Answer 25

Same element (number of protons), but differnet numbers of neutrons

Question 26

Nuclear Decay

Answer 26

Unstable nuclei will decay to become more stable, emitting radiation in the process. These can ionise other atoms/molecules,which can be dangerous.

Question 27

Alpha radiation

Answer 27

Helium nucleus (2p+2n)

Mass= 4

Charge= +2

Ionising power= high

Penetrating ability= Low

Use= Smoke detectors

Question 28

Beta radiation

Answer 28

Fast moving electron

Mass= 0

Charge= -1

Ionising power= medium

Penetrating ability= medium

Use= Thickness gauge

Question 29

Gamma radiation

Answer 29

High energy EM wave

Mass= 0

Charge= 0

Ionising power= low

Penetrating ability= high

Use= Radiotherapy

Question 30

Radioactivity

Answer 30

The rate of decay in a sample of radioactive material. This is equal to the rate of radiation emitted. We can detect some of this radiation with a GM tube, to give us an idea of what the activity is.

Question 31

Half Life

Answer 31

The time it takes for the activity to halve (this is also true for number of unstable nuclei left, and also mass.