matthew187
- Apr 10, 2013
- 5
- Joined
- Apr 10, 2013
- Messages
- 5
Hi I was wondering if some on could check these answers and see if I am along the right lines and if someone could be very kind and help me with the bits that are "question marked" as I don't understand these its just a revision question. many thanks.
A coil of inductance 4H and resistance of 80Ω is connected in parallel with a 200Ω of resistor of negligible inductance across a 200v dc supply. The switch connecting these to the supply is then opened; the coil and resistor remain connected together. State in each case one for immediately before and one for immediately after opening the switch;
a) The current Through the resistor
Immediately before switch opening
200v/ 80ohm =2.5
Immediately after Switch opening
200v / 80ohms = 2.5a
b) The current through the coil
Immediately before Switch opening
200v / 80ohm = 2.5a
Immediately after Switch opening
200v / 80ohm = 2.5a
c)The e.m.f induced in the coil
Immediately before Switch opening
?
Immediately after Switch opening
-2.5a *(200Ω + 80Ω) = -700v
e) The voltage across the coil
Immediately before Switch opening
?
Immediately after Switch opening
-2.5a * 200ohms = -500v
A coil of inductance 4H and resistance of 80Ω is connected in parallel with a 200Ω of resistor of negligible inductance across a 200v dc supply. The switch connecting these to the supply is then opened; the coil and resistor remain connected together. State in each case one for immediately before and one for immediately after opening the switch;
a) The current Through the resistor
Immediately before switch opening
200v/ 80ohm =2.5
Immediately after Switch opening
200v / 80ohms = 2.5a
b) The current through the coil
Immediately before Switch opening
200v / 80ohm = 2.5a
Immediately after Switch opening
200v / 80ohm = 2.5a
c)The e.m.f induced in the coil
Immediately before Switch opening
?
Immediately after Switch opening
-2.5a *(200Ω + 80Ω) = -700v
e) The voltage across the coil
Immediately before Switch opening
?
Immediately after Switch opening
-2.5a * 200ohms = -500v