Paper 1 Electric Fields Answers

Q	Answer	Reason
1	A	Definition: $E=F/q$ for a positive test charge.
2	B	Field direction is the direction of force on a positive test charge.
3	B	$E=kQ/r^2$.
4	C	Potential is work done per unit positive charge from infinity.
5	B	Potential has magnitude and sign but no direction.
6	A	Same potential means $\Delta V=0$, so $W=q\Delta V=0$.
7	C	Field is normal to equipotentials.
8	A	Uniform plate field uses $E=V/d$.
9	B	For a negative charge, the force is opposite to $\vec{E}$.
10	A	$\Delta U=q\Delta V$.
11	B	Coulomb law is inverse square.
12	B	Electric field is a vector.
13	C	Potential is scalar and signed.
14	C	Constant transverse acceleration gives parabolic motion.
15	A	Force is charge times field vector.
16	B	$E=V/d$.
17	A	Equivalent field units.
18	B	Closer field lines represent stronger field.
19	A	$V=kQ/r$ for positive $Q$.
20	B	A small positive test charge defines field without strong disturbance.