Original questions for every topic, with worked explanations and feedback on written answers.
Multiple choice
Worked or timed
Short response
Calculations and explanations on a stimulus
Written answers
Read against the mark points, with your next step
Try 4 questions
Question 1
Speed of a 0.050 kg rubber stopper and the centripetal force measured on it.
Speed (m s⁻¹)
Centripetal force (N)
1.0
0.08
2.0
0.33
3.0
0.75
4.0
1.33
A student whirls a 0.050 kg rubber stopper in a horizontal circle of fixed radius and measures the centripetal force at four speeds with a force sensor. The table shows the results. What is the radius of the circle?
Question 2
Electric field strength measured at four distances from a small charged sphere.
Distance from centre r (m)
Field strength E (N C⁻¹)
0.1
3600
0.2
900
0.3
400
0.4
225
A student measures the electric field strength at several distances from the centre of a small charged sphere. The table shows the results. Taking k = 9 × 10⁹ N m² C⁻², what is the charge on the sphere?
Question 3
Energy levels of the hydrogen atom.
level n
energy (eV)
1
−13.6
2
−3.40
3
−1.51
4
−0.85
The table gives energy levels of the hydrogen atom. An electron falls from n = 4 to n = 2. What is the wavelength of the emitted photon? (h = 6.626 × 10⁻³⁴ J s, c = 3 × 10⁸ m s⁻¹, 1 eV = 1.60 × 10⁻¹⁹ J)
Question 4
The six quarks with their symbols, charges and baryon numbers.
Quark
Symbol
Charge (e)
Baryon number
up
u
+2/3
+1/3
down
d
−1/3
+1/3
strange
s
−1/3
+1/3
charm
c
+2/3
+1/3
top
t
+2/3
+1/3
bottom
b
−1/3
+1/3
The table gives the charges of the six quarks. A particle has the quark content s s s (three strange quarks). Which describes the particle?