Advertisements
Advertisements
प्रश्न
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.
उत्तर
It states that electric current flowing through a metallic wire is directly proportional to the potential difference V across its ends provided its temperature remains the same. This is called Ohm's law.
V = IR
Experimental Verification: Reassemble the circuit according to the diagram. The circuit consists of a battery, an unknown resistance, a voltmeter with its positive terminal facing the battery's anode, and a rheostat and ammeter connected in series. With the key closed, and the rheostat set to zero, the ammeter and voltmeter should display the lowest possible readings. After that, the rheostat is adjusted step-by-step, and the values of A and V are recorded at each interval. The ratio of `"V"/"I"` is always found to be constant. This verifies Ohm's Law.
The temperature and other physical parameters of the conductor must be kept constant.
APPEARS IN
संबंधित प्रश्न
Name the unit of electrical resistance and give its symbol.
In a conductor 6.25 × `10^16` electrons flow from its end A to B in 2 s. Find the current flowing through the conductor (e = 1.6 × `10^-19` C)
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
- Name and state the law which relates the potential difference and current in a conductor.
- What is the necessary condition for a conductor to obey the law named above in part (a) ?
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?
A metal rod of length 10 cm and a rectangular cross-section of 1 cm × `1/2` cm is connected to a battery across opposite faces. The resistance will be ______.
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?
You are provided with a resistor, a key, an ammeter, a voltmeter, four cells of 1.5 V each and few connecting wires. Using circuit components, draw a labelled circuit diagram to show the setup to study Ohm's law.
State the relationship between potential difference (V) across the resistor and the current (I) flowing through it. Also draw V-I graph, taking V on the X-axis.
The voltage - current readings of a certain material are shown in the table given below:
| Voltage (V) | 10 V | 20 V | 30 V |
| Current (I) | 2 A | 3 A | 4 A |
Study the table.
- State whether the conductor used is ohmic or non-ohmic.
- Justify your answer.
- State Ohm's law.
