Science

Question 1

Gas was used to heat the water in the house in 2015 state how the figures allow you to come to this conclusion

Answer 1

Gas cost has reduced since fitting solar panels

Question 2

In 2015 a house holder Paige $780 for electricity and 950 for gas on 1 January 2016 solar panels were installed on the roof to provide hot water for the house the cost of the solar panels was £4680 in 2016 the householder paid 830 for electricity and 840 for gas. Calculate the expected payback time to recover the cost of the solar panels

Answer 2

Insulation coat (divided by) savings=4680(divided by) 110=42.5 years
950-840=110

Question 3

Explain how an increase in the cost of a unit electricity and a unit of gas would affect the payback Time

Answer 3

Cost of electricity has no effect on payback time more expensive gas unit will reduce payback time as savings will increase

Question 4

During the two years the cost of a unit electricity did not change but the number of extra units of electricity used in 2016 was 300kwh use an equation from page 2 to calculate the cost of a unit of electricity (in pence) during 2015-2016

Answer 4

Total=units used (kWh) x cpu
830-780=50
5000=300xcpu
Divide 5000 by 300
Answer is 16.7p

Question 5

(Fibre glass)
What is loft insulation

Answer 5

Fibreglass ‘wool’ laid on the floor and ceiling traps little pockets of air. This reduces energy loss from the house by conduction and convection

Question 6

In another experiment four metal rods are tested to compare their ability to conduct heat energy. The outcome of the experiment is as follows
Copper(best conductor)
Aluminium
Brass
Iron (poorest conductor)
Explain the detail, the process of conduction in copper in terms of the motion of particles

Answer 6

1.the particles at the hot end gain energy and vibrate more.
2. They collide with their neighbouring particles and pass on vibrations.
3. This happens until it reaches equilibrium
4. Copper has free electrons
5. These electron gain energy and move to the cold end passing it on to the cold end.
6. This speeds up to the transfer of energy

Question 7

Rhys and Elliot have a small piece of an unknown metal. The metal has an irregular shape. To identify the metal they find its density and compare the value to known value of the density of common mental. Describe a method they could use to find the density of the metal.

Answer 7

1. Measure the mass of the object using the weighing scale in g
2. Fill the measuring cylinder with sufficient water to submerge the object e.g 20cm cubed
3. Record the volume
4. Submerge the object
5. Record the volume
6. Calculate the volume= new volume- old volume
7. Calculate density using d=m (divided by) v

Question 8

What is mcb and what does it stand for

Answer 8

Mcbs protect the circuit
Mcbs stands for miniature circuit breakers

Question 9

What does rccb do and what does it stand for

Answer 9

Rccb protects the user and it stand for residual current circuit breakers

Question 10

How does mcbs work

Answer 10

1.use an electromagnetic to open a switch if the current goes above a certain value
2. Can be reset
3. Mcbs switch off the current faster then a fuse

Question 11

How does a rccbs work

Answer 11

1. Turns off circuit when live and neutral wire current is different
2. Rccb are more sensitive then mcb

Question 12

Which one is more sensitive rccb or mcb

Answer 12

Rccb

Question 13

What is the neutral wire live wire and earth wire

Answer 13

Earth wire is the dotted one
Live wire is the outside one
Neutral wire is the inside one

Question 14

What is a fuse

Answer 14

Stops current when it’s too high by melting a wire meaning it will need to be replaced as it’s blown to prevent the device overheating.