H Exp – Electricity and Electronics 03 – e.m.f. and internal resistance with parallel circuits

Aim – To investigate the path of the electron beam in a cathode ray tube.

Instructions

▪ Click on a lamp to screw it in or unscrew it.
▪ Note the current I and the corresponding t.p.d. V values when no lamps are screwed in.
▪ Repeat the above for each case as one, then two, then three lamps are screwed in.
▪ Using Ohm’s Law, copy and complete the final column of the table by calculating the value of the internal resistance of the battery.

No. of lamps lit	Current I (A)	t.p.d. V (V)	“lost volts” (V)	internal resistance (Ω)
0
1
2
3

▪ Wait for Player to load. Best viewed full screen, right-click or on mobile, press and hold and select Enter full screen. Full screen not available on iOS.