A vibrating string is observed with a ruler in its plane. Its equilibrium position is at 12.0 cm on the ruler. The highest and lowest positions are 14.4 cm and 9.6 cm.
.1
Calculate the amplitude in metres.
[2 marks]
.2
A pupil says that increasing amplitude necessarily increases frequency. Evaluate the claim.
[2 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A detector registers 96 counts per minute of background radiation. With a source present it registers 896 counts per minute initially and 496 counts per minute after 12 minutes.
.1
Calculate the initial corrected detected count rate in min−1 (counts per minute).
[2 marks]
.2
Determine the half-life in minutes.
[2 marks]
.3
Explain why the background must be subtracted before comparing the rates.
[2 marks]
7 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
A spring stores 0.72 J when compressed by 0.060 m. It obeys Hooke's law throughout this compression. It launches an initially stationary 0.090 kg toy horizontally; 25% of the stored energy is dissipated.
.1
Calculate the spring constant.
[2 marks]
.2
Calculate the toy's speed when it leaves the spring.
[3 marks]
.3
Explain why the speed cannot be found by treating the dissipated energy as destroyed.
[2 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A 15 Ω resistor carries a current of 0.40 A for 200 s. Its resistance remains constant.
.1
Calculate the resistor's power.
[2 marks]
.2
Calculate the energy transferred in 200 s.
[2 marks]
.3
Predict and explain the effect on power of doubling current at the same resistance.
[2 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Equal hot-water bottles are wrapped in equal-thickness samples of wool, foam and foil. In 10 minutes their temperature falls are 5 °C, 3 °C and 7 °C respectively. The starting temperatures, water masses and room temperatures are the same.
Evaluate the conclusion that foam is always the best insulator. Include evidence, limitations and an improved comparison.
