(a(i))[3]
Show that the rise in the internal energy of the water is 6300 J.
(a(ii))[4]
Determine the highest possible efficiency of the filament lamp.
(b)[1]
Suggest one explanation for this.
Physics 0625 · IGCSE · Energy, work and power
Energy, work and power — practice question
A student carries out an investigation into the efficiency of a filament lamp. Fig. 4.1 shows the filament lamp with its glass bulb placed in water in a beaker. The thermometer reading in the water is $19.0^\circ$C. Only the glass part of the lamp touches the water, and the electrical connections are fully insulated. The lamp is switched on. When the experiment finishes, the temperature of the water is $21.5^\circ$C.