ON16 P52 Q2 LED Voltage

 9702/52/O/N/16: A  student  is  investigating  the  characteristics  of  different  light-emitting  diodes  (LEDs).  Each  LED  needs a minimum potential difference across it to emit light.The circuit is set up as shown in Fig. 2.1. 

The potentiometer is adjusted until the LED just emits light. The potential difference V across the LED is measured.The experiment is repeated for LEDs that emit light of different wavelength λ. It is suggested that V and λare related by the equation V = pλ^q where p and q are constants.

Solutions for October/November 2016 Paper 5 variant 2 question 2 data analysis.

ON11 P52 Q2 Orbit Period

 9702/52/O/N/11: A scientist is observing some of the moons orbiting the planet Jupiter. For six different moons, the scientist records the distance r  from the centre of Jupiter and the period T  of the orbit. It is suggested that T and r are related by the equation \(T^2 = kr^3\) where k is a constant.

Solutions for practical Paper 5 variant 2 Question 2 Oct/Nov 2011 Cambridge A Level Physics.

ON10 P53 Q2 Capacitor Discharge

 9702/53/O/N/10: A student is investigating how the discharge of a capacitor through a resistor depends on the resistance of the resistor. The equipment is set up as shown in Fig. 2.1.

The  student  charges  the  capacitor  of  capacitance C  and  then  discharges  it  through  a  resistor of resistance R. After 15.0 s the student records the potential difference V across the capacitor. The student repeats this procedure for different values of R. 

It is suggested that V and R are related by the equation \(V = V_0 e^{–\frac{t}{CR}}\) where \(V_0\) is the initial potential difference across the capacitor and t is the time over which the capacitor has discharged.

Solutions for practical Paper 5 variant 3 Question 2 Oct/Nov 2010 Cambridge A Level Physics.