Paper 1 Conservation Laws in Physics Answers

Q	Answer	Reason
1	A	System boundary determines what is conserved.
2	B	Momentum is conserved when resultant external impulse is zero or negligible over the interaction.
3	C	Current continuity follows from charge conservation.
4	D	Energy is transferred or transformed but not created or destroyed.
5	B	Nucleon or mass numbers are the upper numbers.
6	C	Proton or nuclear-charge numbers are the lower numbers.
7	A	Mass defect appears as energy.
8	D	Initial total momentum is zero, so the final vector sum is zero.
9	A	Kinetic energy can transform to internal energy.
10	B	Kirchhoff’s first law is charge conservation at a junction.
11	C	Kirchhoff’s second law is energy conservation per unit charge around a loop.
12	A	Boundary mistakes invalidate conservation claims.
13	B	Momentum has direction and is a vector.
14	D	Energy has no direction and is a scalar.
15	A	Mechanical energy can be dissipated to thermal energy outside chosen mechanical store.
16	B	Total charge is constant for an isolated system.
17	A	One nucleon remains one nucleon.
18	C	The loop rule is energy accounting per unit charge.
19	A	Choose system and check external interactions.
20	D	Internal transfers redistribute a conserved quantity without changing the system total.