A resistor is connected to a power supply - Edexcel - GCSE Physics - Question 8 - 2018 - Paper 1

To find the time taken for a charge of 42C to flow at a current of 200 mA, we use the formula:

t = rac{Q}{I}

Substituting in the values:

t = rac{42C}{0.2A} = 210 seconds

To convert seconds to minutes:

t = rac{210}{60} = 3.5 ext{ minutes}

The energy transferred can be calculated using the formula:

$E = V imes Q$

Substituting in the values:

$E = 6.0V imes 42C = 252 ext{ joules}$

The resistor becomes warm due to the collisions between moving electrons and the lattice structure of the resistor. As electrons flow through the resistor, they collide with atoms in the lattice. These collisions transfer energy to the atoms, causing them to vibrate more, which in turn increases the thermal energy of the resistor, resulting in a warmer temperature.

To find the arrangement of the resistors, we first need to calculate the total resistance.

Given:

• Potential difference (V) = 6.0V
• Current (I) = 1.2A

Using Ohm's law:

R = rac{V}{I} = rac{6.0V}{1.2A} = 5 ext{ ohms}

Each resistor has a resistance of 100 ohms. If they were in series, the total resistance would be:

$R_{total ext{ (series)}} = 100 + 100 = 200 ext{ ohms}$

Since 5 ohms is less than 200 ohms, the resistors must be connected in parallel. This arrangement allows for a lower total resistance, thus supporting the current of 1.2A.