A sensor contains a rotating metal disc. A solid block remains in contact with the disc while it turns, allowing an electrical signal to pass from the disc through the block.

Blocks of four materials, each with the same dimensions, were tested under the same conditions.

Material	Electrical resistance ( $Ω\Omega$ )	Frictional force ( $N\text{N}$ )
Aluminium oxide	greater than 1 000 000	4.2
Copper	0.05	3.8
Diamond	greater than 1 000 000	1.0
Graphite	0.80	1.2

The block is suitable if:

its electrical resistance is no more than 1.0 Ω
the frictional force is no more than 1.5 N.

Which material should be used for the block?

Explain your answer using the data and the structure and bonding in the material.

A sensor contains a rotating metal disc. A solid block remains in contact with the disc while it turns, allowing an electrical signal to pass from the disc through the block.

Blocks of four materials, each with the same dimensions, were tested under the same conditions.

Material	Electrical resistance ( $Ω\Omega$ )	Frictional force ( $N\text{N}$ )
Aluminium oxide	greater than 1 000 000	4.2
Copper	0.05	3.8
Diamond	greater than 1 000 000	1.0
Graphite	0.80	1.2

The block is suitable if:

its electrical resistance is no more than 1.0 Ω
the frictional force is no more than 1.5 N.

Which material should be used for the block?

Explain your answer using the data and the structure and bonding in the material.

2.3 Structure and bonding of carbon

Question 20

Markscheme

2.3 Structure and bonding of carbon

Question 20

Markscheme

2.3 Structure and bonding of carbon

Question 20

2.3 Structure and bonding of carbon Questions

2.3 Structure and bonding of carbon

Question 20

2.3 Structure and bonding of carbon Questions