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 १
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.
उत्तर २
The maximum current that can be drawn from a source of emf E and internal resistance r is Imax = E/r. If E is low, r must be extremely small to allow a high value of Imax.
APPEARS IN
संबंधित प्रश्न
Is Ohm’s law universally applicable for all conducting elements? If not, give examples of elements which do not obey Ohm’s law.
Name the unit of electrical resistance and give its symbol.
Four resistances of 16 ohms each are connected in parallel. Four such combinations are connected in series. What is the total resistance?
What is the necessary condition for a conductor to obey Ohm’s law?
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?
An electric bulb draws 1.2 A current at 6.0 V. Find the resistance of filament of bulb while glowing.
How does an increase in the temperature affect the specific resistance of a :
(i) Metal and
(ii) Semiconductor ?
Define the following:
Coulomb
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.
SI unit of resistance is:
The ratio of the potential difference to the current is known as ________.
State Ohm’s law.
Explain the equivalent resistance of a parallel resistor network.
An electronics hobbyist is building a radio which requires 150 Ω in her circuit, but she has only 220 Ω, 79 Ω, and 92 Ω resistors available. How can she connect the available resistors to get the desired value of resistance?
The unit of specific resistance is ____________.
The temperature of a conductor is increased. The graph best showing the variation of its resistance is:
A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R1, R2 and R3 respectively. Which of the following is hue?
Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1 mm. Conductor B is a hollow tube of outer diameter 2 mm and inner diameter 1 mm. Find the ratio of resistance RA to RB.
