IB DP Physics Mock Exam SL Paper 1A Set 5 - 2025 Syllabus

IB DP Physics Mock Exam SL Paper 1A Set 5

Prepare for the IB DP Physics Mock Exam SL Paper 1A Set 5 with our comprehensive mock exam set 5. Test your knowledge and understanding of key concepts with challenging questions covering all essential topics. Identify areas for improvement and boost your confidence for the real exam

IB DP Physics Mock Tests -All Sets

Question

The diagram below shows a snapshot of a transverse wave on a rope. Points \(P\) and \(Q\) are two points on the rope at the positions shown. The subsequent motion of \(P\) is upwards.

What is the direction of motion of \(Q\) and the direction of travel of the wave?

Option	Direction of motion of \(Q\)	Direction of travel of the wave
(A)	Upwards	Left to right
(B)	Downwards	Left to right
(C)	Upwards	Right to left
(D)	Downwards	Right to left

▶️ Answer/Explanation

Detailed solution

At point \(P\), the wave profile is rising (positive slope) and the particle is stated to move upwards next. For a travelling wave, if the particle motion has the same sign as the slope at that point, the wave is travelling right to left.

Point \(Q\) is also on a rising part of the wave (positive slope). With the wave travelling right to left, \(Q\) will therefore move upwards.

✅ Answer: (C)

Question

Two identical isolated point charges, \(Q_{1}\) and \(Q_{2}\), are placed a distance \(d\) apart. The electrostatic force acting on each charge is \(F\). The charge on \(Q_{1}\) is then reduced to half its original value. What is the electrostatic force acting on each charge now?

	Force on \(Q_1\)	Force on \(Q_2\)
(A)	\(F\)	\(F\)
(B)	\(F\)	\(\frac{F}{2}\)
(C)	\(\frac{F}{2}\)	\(\frac{F}{2}\)
(D)	\(\frac{F}{2}\)	\(F\)

▶️ Answer/Explanation

Detailed solution

1. Apply Coulomb’s Law:
\(F \propto Q_1 Q_2\).
If \(Q_1\) is reduced to \(Q_1/2\), the new force becomes \(\frac{1}{2}F\).

2. Apply Newton’s Third Law:
The forces between two interacting charges form an action–reaction pair and are equal in magnitude.
Therefore, both \(Q_1\) and \(Q_2\) experience a force of magnitude \(\frac{F}{2}\).

✅ Answer: (C)

Question

Thorium-232 (\(_{90}^{232}\text{Th}\)) is a radioactive nuclide. It undergoes an alpha decay followed by a beta minus (\(\beta^-\)) decay. How many protons and neutrons are present in the resulting nuclide?

	Number of protons	Number of neutrons
(A)	\(87\)	\(139\)
(B)	\(87\)	\(141\)
(C)	\(89\)	\(139\)
(D)	\(89\)	\(141\)

▶️ Answer/Explanation

Detailed solution

1. Alpha Decay (\(_{2}^{4}\text{He}\)):
Nucleon number (A) decreases by \(4\): \(232 – 4 = 228\).
Proton number (Z) decreases by \(2\): \(90 – 2 = 88\).

2. Beta Minus Decay (\(_{-1}^{0}\beta\)):
Nucleon number (A) remains unchanged: \(228\).
Proton number (Z) increases by \(1\): \(88 + 1 = 89\).

3. Determine Protons and Neutrons:
Number of protons \(= 89\).
Number of neutrons \(= 228 – 89 = 139\).
✅ Answer: (C)

IB DP Physics Mock Exam SL Paper 1A Set 5 - 2025 Syllabus