A hollow, transparent plastic tube is placed on a horizontal surface. A wire carrying a current is wound once around the tube to
1 answer:
When wire is coiled on the plastic tube and current flow through that wire then the system will behave like a solenoid in which current flows through the coiled wires and then it produce magnetic field along the axis of solenoid
So here it will also produce magnetic field along the axis of solenoid and then due to this magnetic field the compass placed inside the tube will experience torque on its needle due to which it will have tendency to oriented along the direction of magnetic field.
So here we can say that compass needle will lie along the axis of the plastic tube.
here magnetic field along the axis of tube will be given same as solenoid which is given as
so here direction of compass needle is axis of the tube
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Answer:
Approximately .
Approximately . (assumption: the LED here is an Ohmic resistor.)
Explanation:
The two resistors here and
are connected in parallel. Their effective resistance would be equal to
.
The current in a serial circuit is supposed to be the same everywhere. In this case, the current through the LED should be . That should also be the current through the effective
resistor. Make sure all values are in standard units. The voltage drop across that resistor would be
.
The voltage drop across the entire circuit would equal to
- the voltage drop across the resistors, plus
- the voltage drop across the LED.
In this case, that value would be equal to . That's the voltage that needs to be supplied to the circuit to achieve a current of
through the LED.
Assuming that the LED is an Ohmic resistor. In other words, assume that its resistance is the same for all currents. Calculate its resistance:
.
The resistance of a serial circuit is equal to the resistance of its parts. In this case,
.
Again, the current in a serial circuit is the same in all appliances.
.