cameroon gce A level June 2024 physics 2
cameroon gce A level June 2024 physics 2
From Biot-Savart law, it can be shown that the size of the magnetic flux density (B) inside the solenoid is given by
” ‘ ” B= fitnl
•Where p is the permeability of the medium, n is the number of turns of coil per unit length and / is the .
current in the solenoid. • .
Draw a diagram to show the magnetic flux pattern of the solenoid \n figure 1.
using only units show that the above equation is homogenous
If steel has a relative permeability of 2000 and the above solenoid has 250 turns, %
determine the magnetic field strength inside the solenoid.
(a)
(b)
(c)
(6 marks)
Copper has about 8.49 x 1028 charge carriers per unit volume and a resistivity of 1.68 x 108 Q m. In figure 2,
a copper cable with a cross-sectional area of 0.27 mm2 is connected in series with a battery. The connecting
cables have negligible resistance.
9
© *I–
switch
A
Flynn’ 2
752 cm
.r • vi
copper cable \C’
a) If the ammeter reading is 6.04 A, determine;
the drift velocity of charge carriers through the copper wire
the reading of the voltmeter
b) Explain why the reading of the voltmeter increases when the switch is opened.
i)
ii)
(6 marks)
Figure 3 shows a brick wall of thickness, x and surface area, A. The heat entering the inner wall is Q, at
temperature T| and that leaving the outer wall is Q2 at temperature T2.
(a) State two conditions for the heat conduction through the wall above to reach a steady state.
(b) Define temperature gradient and write an expression for it for the wall above.
(c) If the wall is 12.0 cm thick, with a heat How surface of 0.08 m 2 and is made of brick of thermal conductivity
0.S0 W in ‘ K’\
i ) Determine the thermal resistance of the wall.
ii) Hence or otherwise, calculate the rate of heat How through the wall if T| is 355 K and T2 is
330 K. (6 marks)
According to kinetic theory, the pressure of an ideal gas is given by the equation:
r =^ pc2
Where P is the pressure of the gas, p is its density and c 2 is the mean-square speed of the molecules.
(a) State TWO assumptions used to derive this equation.
(b) Use the above equation to show that c 2 is related to the absolute temperature of the gas by;
3 3RT
c ~
M
Where R is the molar gas constant, T is the absolute temperature of the gas and M is the molar mass of
the gas.
(c) The root-mean-square (rms) speed of a certain gas is 850 m s’1 at a room temperature of
30.0 °C. Determine the root-mean-square speed of the molecules if the gas is heated to a temperature of
150 °C. (6 marks
