cameroon gce advanced level June 2022 physics 2

cameroon gce advanced level June 2022 physics 2

cameroon gce advanced level June 2022 physics 2

SECTION I
(One hour)
Answer all Questions in this Section.
l . Tlie energy generated per unit time by a wind turbine is given by the equation E = – p A K v 3 N
where p is the air density, A is the area swept by the blade, v is the wind velocity, K is the coefficient of
performance and N is the generator efficiency.
(a) Explain with the help of an example why homogeneity of a physical equation is not a sufficient
condition for the correctness of the equation.
(b) Determine the base units of K. (6 marks)
2. An electric circuit is made by connecting in series a resistor of resistance 80 H, an inductor of inductance 0.4 H
and a capacitor of capacitance 125 pF to an alternating power source of Vrms = 220 V and frequency 50 Hz,
(a) State any one use of such a circuit in daily life.
(b) Calculate the impedance, Z, and the root mean square value of the current in the circuit.
(c) Calculate the resonant frequency f0, and the current in the circuit at resonance. (6 marks)
3.
. (a). What is meant by “the moment of a force”?
(b). State one.condition necessary for a body to be in equilibrium on a plane.
(c). Figure I shows a uniform plank of weight 6 N and length a, inclined at an angle 0.
Calculate 0 given that the system is in equilibrium.
i4
Figure 1 4 N*
60? (6 marks)
16 N
4. (a) Define self-inductance.
(b) A solenoid of 500 turns and diameter 10 cm is made from a conducting wire of diameter d =lmm. If there
are no spaces between the turns, calculate the,
i) total length of the coil needed for the solenoid.
ii) current that must flow in the turns to produce a field strength of 0.15 T at the centre of the solenoid.
iii) flux linking the turns of this solenoid when it is supplied with the current calculated.