james

During electrolysis of copper sulphate, a steady current of 0.40 A is recorded in the circuit for a period of 600 seconds. During the electrolysis positive copper ions reach the cathode and each ion gains two electrons to form a copper atom thereby increasing the mass of the cathode. At the same time copper atoms form copper ions at the anode maintaining a constant concentration for the solution.

If the mass of a single copper atom is 1.06 × 10–25 kg, what is the total increase in mass for the cathode during this experiment?

A copper wire with a radius r has a current I passing through it. The mean drift velocity of the electrons is v1. At a junction the wire is joined to a second wire made of identical copper but with a radius area 3r. In this wire the mean drift velocity for the electrons is v2.

What is the ratio of the drift velocities for the electrons in the two wires?

A metal block of mass 1.5 kg is placed on a smooth inclined slope 40 dgrees. The block is released and slides to the bottom of the ramp, a distance of 0.75 m.

Assume an average frictional force (F) of 4.0 N along the slope during the slide.

g = 9.81 m s–2.

Calculate the speed of the block as it reaches the bottom of the slope.

A cube of aluminium with sides of 5.00 cm is placed into a large container of mercury as shown in the figure.

To what depth will the base of the cube sink?

Density of mercury = 13.5 g cm–3. Density of aluminium = 2.70 g cm–3.

During a swimming lesson a weighted toy consisting of a rigid air-filled cylinder, of length 10.0 cm and diameter 2.00 cm, attached to a weight by a thin string, is thrown into a pool. The toy sinks and the cylinder stands upright just above the bottom of the pool.

Calculate the upthrust acting on the cylinder.

Density of water is 1000 kg m–3. Take g as 9.81 N kg–1.

To allow a projectile to travel through the air, a torque is applied as the projectile is fired to give it a ‘spin’ so that it rotates in a direction perpendicular to the direction of launch.

A projectile has a radius of 0.45 mm, and a torque of 0.50 N m is applied during firing.

Assuming that the torque is provided by a couple, determine the size of one of these forces.