Advertisements
Advertisements
प्रश्न
Write the SI unit of resistivity
उत्तर
The SI unit of resistivity is ohm-meter (Ω - m)
APPEARS IN
संबंधित प्रश्न
What will be the change in the current if the potential difference is kept constant and the resistance of the circuit is made four times?
- It will remain unchanged.
- It will become four times.
- It will become one-fourth.
- It will become half.
Find the resistance of a conductor if 0.24 A current is passing through it and a potential difference of 24 V is applied across it.
Write the formula of resistivity
An electrical bulb is marked 200V, 100W. Calculate the electrical resistance of its filament. If five such
bulbs are connected in series to a 200V supply, how much current will flow through them?
Ohm's law gives a relationship between:
(a) current and resistance
(b) resistance and potential difference
(c) potential difference and electric charge
(d) current and potential difference
How should the two resistances of 2 ohms each be connected so as to produce an equivalent resistance of 1 ohm?
How much energy is consumed when a current of 5 amperes flows through the filament (or element) of a heater having resistance of 100 ohms for two hours? Express it in joules.
A resistance of 40 ohms and one of 60 ohms are arranged in series across 220 volt supply. Find the heat in joules produced by this combination of resistances in half a minute.
State Ohm’s law and draw a neat labelled circuit diagram containing a battery, a key, a voltmeter, an ammeter, a rheostat and an unknown resistance to verify it.
In an experiment of verification of Ohm’s law following observations are obtained.
|
Potential difference V (in volt) |
0.5 | 1.0 | 1.5 | 2.0 | 2.5 |
| current I (in ampere) | 0.2 | 0.4 | 0.6 | 0.8 | 1.0 |
Draw a V-I graph and use this graph to find:
- the potential difference V when the current I is 0.5 A,
- the current I when the potential difference V is 0.75 V,
- the resistance in a circuit.
A wire of resistance 3 ohm and length 10 cm is stretched to length 30 cm. Assuming that it has a uniform cross section, what will be its new resistance?
A wire of resistance 9 ohm having length 30 cm is tripled on itself. What is its new resistance?
Show by a diagram how two resistors R1 and R2 are joined in parallel. Obtain an expression for the total resistance of the combination.
Calculate the effective resistance across AB?
Consider the sacle of voltmeter shown in the diagram and answer the following questions :
(a) What is the least count of the voltmeter?
(b) What is the reading shown by the voltmeter ?
(c) If the voltmeter is connected across a resistor of 20 `Omega` how much current is flowing through the resistor?
Define the following:
(i) Coulomb
(ii) Ohm
Rewrite the following statement by selecting the correct option.
The S.I. unit of resistance is __________.
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 is non-ohmic resistor?
What are ohmic conductors? Give one exmaple. Draw a graph showing the current-voltage relationship for an ohmic conductor.
What are non-ohmic conductors? Give one exmaple. Draw a current-voltage graph for a non-ohmic conductor.
What is non ohmic device?
Define temperature coefficient of resistance.
Which of the following I-V graph represents ohmic conductors?
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 true?
Ohm's law deals with the relationship between ______
What is the resistance of a conductor through which a current of 0.5 A flows when a potential difference of 2V is applied across its ends?
Let the resistance of an electrical device remain constant, while the potential difference across its two ends decreases to one fourth of its initial value. What change will occur in the current through it? State the law which helps us in solving the above stated question.
What is meant by resistance of a conductor ? Define its SI unit.
The resistance of a resistor is reduced to half of its initial value. If other parameters of the electrical circuit remain unaltered, the amount of heat produced in the resistor will become ______.
Why should an ammeter have low resistance?
