Physics
A cell of e.m.f. ε and internal resistance r sends a current of 1.0 A when it is connected to an external resistance of 1.9 ohm. But it sends a current of 0.5 A when it is connected to an external resistance of 3.9 ohm. Calculate the values of ε and r.
Related Questions
A music system draws a current of 400 mA when connected to a 12 V battery.
(a) What is the resistance of the music system ?
(b) The music system if left playing for several hours and finally the battery voltage drops and the music system stops playing when the current drops to 320 mA. At what battery voltage does the music system stop playing.
Four resistors each of resistance 5 Ω are connected in parallel. What is the effective resistance?
A cell of emf 1.8 V and internal resistance 2 Ω is connected in series with an ammeter of resistance 0.7 Ω and resistance of 4.5 Ω as shown in figure.
(a) What would be the reading of the ammeter?
(b) What is the potential difference across the terminals of the cell ?
Two resistors having resistance 8 Ω and 12 Ω are connected in parallel. Find their equivalent resistance.