No questions found
Energy is stored in a metal wire that is extended elastically.
(a) Explain what is meant by extended elastically. [2]
(b) Show that the SI units of energy per unit volume are $ \text{kg m}^{-1} \text{s}^{-2} $. [2]
(c) For a wire extended elastically, the elastic energy per unit volume $ X $ is given by
$$ X = C \varepsilon^2 E $$
where $ C $ is a constant,
$ \varepsilon $ is the strain of the wire,
and $ E $ is the Young modulus of the wire.
Show that $ C $ has no units. [3]
586
538
537
(a) Distinguish between mass and weight. [2]
(b) An object O of mass 4.9 kg is suspended by a rope A that is fixed at point P. The object is pulled to one side and held in equilibrium by a second rope B, as shown in Fig. 2.1.
Rope A is at an angle \( \theta \) to the horizontal and rope B is horizontal. The tension in rope A is 69 N and the tension in rope B is \( T \).
(i) On Fig. 2.1, draw arrows to represent the directions of all the forces acting on object O. [2]
(ii) Calculate
the angle \( \theta \), [3]
the tension \( T \). [2]
513
537
513
(a) An object falls vertically from rest through air. State and explain the energy conversions that occur as the object falls. [3]
(b) A ball of mass 150 g is thrown vertically upwards with an initial speed of 25 $ms^-1$.
(i) Calculate the initial kinetic energy of the ball. [3]
(ii) The ball reaches a height of 21 m above the point of release.
For the ball rising to this height, calculate
1. the loss of energy of the ball to air resistance, [3]
2. the average force due to the air resistance. [2]
586
594
575
(a) Define $\textit{pressure}$. [1]
(b) Use the kinetic model to explain the pressure exerted by a gas. [4]
(c) Explain whether the collisions between the molecules of an ideal gas are elastic or inelastic. [2]
555
545
555
(a) State three conditions required for maxima to be formed in an interference pattern produced by two sources of microwaves. [3]
(b) A microwave source M emits microwaves of frequency 12 GHz. Show that the wavelength of the microwaves is 0.025 m. [3]
(c) Two slits \( S_1 \) and \( S_2 \) are placed in front of the microwave source M described in (b), as shown in Fig 5.1.
The distances \( S_1O \) and \( S_2O \) are equal. A microwave detector is moved from O to P. The distance \( S_1P \) is 0.75 m and the distance \( S_2P \) is 0.90 m.
The microwave detector gives a maximum reading at O.
State the variation in the readings on the microwave detector as it is moved slowly along the line from O to P. [3]
(d) The microwave source M is replaced by a source of coherent light.
State two changes that must be made to the slits in Fig. 5.1 in order to observe an interference pattern. [2]
584
576
533
Two resistors A and B have resistances $R_1$ and $R_2$ respectively. The resistors are connected in series with a battery, as shown in Fig. 6.1.
The battery has electromotive force (e.m.f.) $E$ and zero internal resistance.
(a) State the energy transformation that occurs in
(i) the battery,
.......................................................................................................... [1]
(ii) the resistors.
.......................................................................................................... [1]
(b) The current in the circuit is $I$.
State the rate of energy transformation in
(i) the battery,
.......................................................................................................... [1]
(ii) the resistor A.
.......................................................................................................... [1]
(c) The resistors are made from metal wires. Data for the resistors are given in Fig. 6.2.
[Table_1]
Use information from Fig. 6.2 to determine the ratio
\[ \text{power dissipated in A} \over \text{power dissipated in B} \]
ratio = ......................................................... [3]
(d) The resistors A and B are connected in parallel across the same battery of e.m.f. $E$. Determine the ratio
\[ \text{power dissipated in A} \over \text{power dissipated in B} \]
ratio = ......................................................... [2]
536
505
588
(a) Describe the two main results of the $\alpha$-particle scattering experiment.
result 1: ...................................................
............................................................................................................
result 2: ...................................................
............................................................................................................
[3]
(b) Relate each of the results in (a) with the conclusions that were made about the nature of atoms.
result 1: ...................................................
............................................................................................................
result 2: ...................................................
............................................................................................................
[3]
543
537
590
