Advertisements
Advertisements
प्रश्न
A low voltage supply from which one needs high currents must have very low internal resistance. Why?
Answer the following giving reason:
A low voltage supply from which one needs high currents must have very low internal resistance. Why?
Advertisements
उत्तर
According to Ohm’s law, the relation for the potential is V = IR
Voltage (V) is directly proportional to the current (I).
R is the internal resistance of the source.
I = `V/R`
If V is low, then R must be very low, so that a high current can be drawn from the source.
संबंधित प्रश्न
Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
What is an Ohmic resistor?
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?
In the circuit shown in the figure, find the total resistance of the circuit and the current in the arm AD.
Two metallic spheres A and B kept on insulating stands are in contact with each other. A positively charged rod P is brought near the sphere A as shown in the figure. The two spheres are separated from each other, and the rod P is removed. What will be the nature of charges on spheres A and B?
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.
State and define Ohm’s law.
State the limitations of Ohm’s law.
What are ohmic conductors? Give one exmaple. Draw a graph showing the current-voltage relationship for an ohmic conductor.
State microscopic form of Ohm’s law.
What is ohmic device?
The resistance of a nichrome wire at 0°C is 10Ω. If its temperature coefficient of resistivity of nichrome is 0.004/ °C, find its resistance of the wire at boiling point of water. Comment on the result.
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
Which of the following is correct for V-I graph of a good conductor?
The variable resistance is called ____________.
Assertion: The statement of Ohm’s law is K = IR.
Reason: V = IR is the equation which defines resistance.
Consider a current carrying wire (current I) in the shape of a circle. Note that as the current progresses along the wire, the direction of j (current density) changes in an exact manner, while the current I remain unaffected. The agent that is essentially responsible for is ______.
Two cells of same emf E but internal resistance r1 and r2 are connected in series to an external resistor R (Figure). What should be the value of R so that the potential difference across the terminals of the first cell becomes zero.
A current of 0.8 A flows in a conductor of 40 Ω for 1 minute. The heat produced in the conductor will be ______.
