Energy and amont left after half equation

Question 1

the energy in the nuclear store can be released by

Answer 1

radioactive decay

Question 2

The internal store of energy is the sum of

Answer 2

the kinetic energy stored in the particles of an object and the chemical energy stored in chemical bonds between particles in the object

Question 3

The main stores of energy are

Answer 3

Kinetic
Gravitational potential
Chemical
Elastic potential
Nuclear
Internal
Magnetic
Electrostatic

Question 4

increasing a body’s temperature increases the…

Answer 4

the energy in its internal store

Question 5

elastic potential energy=

Answer 5

1/2×spring constant×extension 2

Question 6

Energy transferred from one object to another via a force is an example of

Answer 6

mechanical work.

Question 7

what is Electrical work

Answer 7

An electrical current transfers energy from one object to another.

Question 8

what is Mechanical
work

Answer 8

Energy transferred from one object to another via a force.

Question 9

More work is done if you…

Answer 9

-push with the same force for a longer distance.
-push with a larger force for the same distance.

Question 10

Work done =

Answer 10

force x distance

Question 11

energy=

Answer 11

potential difference×current×time

Question 12

energy=

Answer 12

power×time

Question 13

power=

Answer 13

work done/time

Question 14

Efficiency =

Answer 14

(useful power output/total power input) x 100

Question 15

Power (watts, W) =

Answer 15

work done (joules, J) ÷ time (seconds, s)

Question 16

The higher the thermal conductivity of a material the

Answer 16

higher the rate of energy transfer by conduction across the material.

Question 17

how big is a atom’s radius?

Answer 17

1 × 10-10 metres.

Question 18

The radius of a nucleus is less than ———– of the radius of an atom.

Answer 18

1/10 000

Question 19

When atoms emit electromagnetic radiation

Answer 19

electrons can drop to a lower energy level, closer to the nucleus

Question 20

When atoms absorb electromagnetic radiation,

Answer 20

electrons move to a higher energy level further away from the nucleus.

Question 21

Why would the alpha particles be deflected by a smaller angle if the thin metal foil was made of a lighter element?

Answer 21

The nuclei of lighter elements contain fewer protons. This means they have a lower charge. Each alpha particle will, therefore, experience a smaller electric force acting on it and so deflect by a smaller angle.

Question 22

density kg/m3=

Answer 22

mass(kg)/volume(m3)

Question 23

The specific heat capacity of a substance is the amount of

Answer 23

energy needed to increase the temperature of 1 kg of that substance by 1°C.

Question 24

thermal capacity=

Answer 24

mass×specific heat capacity

Question 25

what is latent heat,

Answer 25

energy absorbed or released by a substance during a change in its physical state (phase) that occurs without changing its temperature.

Question 26

When a solid becomes a liquid or a liquid becomes a solid, this hidden energy is called the latent heat of

Answer 26

fusion.

Question 27

When a gas becomes a liquid, or a liquid becomes a gas, this hidden energy is called the latent heat of

Answer 27

vaporisation.

Question 28

What happens to the energy supplied during a change of state at both the melting and boiling points?

Answer 28

kinetic energy remains constant
potential energy increases

Question 29

How is blood flow in the body imaged using radiation?

Answer 29

Gamma-emitting isotopes are injected into the body.
We can trace the gamma-emitting particles as they travel in the blood around the body.
We can use the detected signal to image the organs in the body.

Question 30

The half-life is the

Answer 30

average time taken for the number of radioactive nuclei to halve

Question 31

The half-life for any isotope of an element is ——-.

Answer 31

constant

Question 32

substance radiation=

Answer 32

total radiation−background radiation

Question 33

To find the half-life of an isotope, measure the —– taken for the activity of the sample to halve.

Answer 33

time

Question 34

How would you measure count rate to work out a substance’s half-life

Answer 34

geiger meter

Question 35

A=

Answer 35

A1 x (1/2)to the power of t/h

Question 36

(Equation- half life) New mass =

Answer 36

original mass x (1/2) to the power of t/h

Question 37

in which part of a transformer is a changing magnetic field induced?

Answer 37

in the iron core

Question 38

Suggest a reason why DC (direct current) is not used for the National Grid.

Answer 38

Transformers are used to minimise wasted energy during transmission. DC does not work with transformers. This is because the secondary coil of a transformer needs to be linked with an alternating magnetic field. Only an AC (alternating current) supply can achieve this.

Question 39

what is The voltage used in home plug sockets.

Answer 39

230

Question 40

what is The voltage at which electricity is generated.

Answer 40

15000

Question 41

what is The voltage at which electricity is transmitted over long distance to reduce losses.

Answer 41

400,000

Question 42

Which only pure metals that can be turned into a magnet?

Answer 42

cobalt, nickel, iron

Question 43

transformers are able to change the voltage in wires carrying ——-

Answer 43

alternating currents.

Question 44

In which direction do magnetic field lines point?

Answer 44

north to south

Question 45

1 A =

Answer 45

1000 mA

Question 46

Explain why the potential difference across the thermistor changes as the temperature in the house decreases.

Answer 46

Their resistance decreases as the temperature increases. At low temperatures, the resistance of a thermistor is high, and little current can flow through them

Question 47

potential difference =

Answer 47

current × resistance