Advertisements
Advertisements
Question
State Ohm's Law. Represent it mathematically.
Solution
According to Ohm's law, "Electric current through a metallic conductor is directly proportional to potential difference across the conductor of the circuit provided that temperature remains constant."
Mathematical expression for Ohm's Law: I ∝ V.
Or V = IR
Or I = `"V"/"R"`
Where, R = constant called resistance of a given metal.
APPEARS IN
RELATED QUESTIONS
Name the law which is illustrated by the above V−I graph.
What is an ohmic resistor? Give one example of an ohmic resistor. Draw a graph to show its current voltage relationship. How is the resistance of the resistor determined from this graph?
A car bulb connected to a 12 volt battery draws 2 A current when glowing. What is the resistance of the filament of the bulb? Will the resistance be more same or less when the bulb is not glowing?
Show by a diagram how two resistors R1 and R2 are joined in parallel. Obtain an expression for the total resistance of the combination.
What is meant by the drift speed of free electrons?
State the relation correlating the electric current flowing in a conductor and the voltage applied across it. Also, draw a graph to show this. relationship.
Define temperature coefficient of resistance.
Two cells each of 5V are connected in series across an 8Ω resistor and three parallel resistors of 4Ω, 6Ω, and 12Ω. Draw a circuit diagram for the above arrangement. Calculate
- the current drawn from the cell
- current through each resistor
Suppose there is a circuit consisting of only resistances and batteries and we have to double (or increase it to n-times) all voltages and all resistances. Show that currents are unaltered. Do this for circuit of Example 3.7 in the NCERT Text Book for Class XII.
