iGCSE Physics (0625) 4.2.1 Electric charge Paper 4 -Exam Style Questions- New Syllabus

Correct Answer: A region where an electric charge experiences a force.

Detailed solution: An electric field is formally defined as a region of space where an electric charge experiences a force. It represents the influence a charge has on its surroundings, meaning any other charged object placed within this specific region will be either attracted or repelled depending on its relative polarity.

Correct Answer: Four radial straight field lines starting at the charge, with at least one arrow pointing towards the charge.

Detailed solution: For an isolated negative point charge, the electric field lines must be drawn radially inwards. You should draw exactly four straight lines distributed evenly around the charge. The arrows on these lines must point towards the central negative charge, indicating the direction of the electrostatic force that a positive test charge would experience.

Correct Answer: $1600\text{ C}$

Detailed solution: Potential difference $V$ is defined as the energy transferred $W$ per unit charge $Q$, given by the equation $V = \frac{W}{Q}$. Rearranging this to solve for charge gives $Q = \frac{W}{V}$. First, convert the energy to Joules: $W = 4.5 \times 10^5\text{ MJ} = 4.5 \times 10^{11}\text{ J}$. Substituting the known values yields $Q = \frac{4.5 \times 10^{11}}{2.9 \times 10^8} \approx 1551.7\text{ C}$, which rounds to $1600\text{ C}$ (to two significant figures).

Correct Answer: $240\text{ C}$

Detailed solution: Electric current $I$ is the rate of flow of charge $Q$ over time $t$, expressed mathematically as $I = \frac{Q}{t}$. Rearranging this formula to solve for the charge gives $Q = I \times t$. By substituting the given values of current ($2.0\text{ A}$) and time ($120\text{ s}$), we calculate the total charge that flows as $Q = 2.0 \times 120 = 240\text{ C}$.