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प्रश्न
Define the term resistivity.
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उत्तर
The resistivity of a material is the resistance of a wire of that material of unit length and unit area of cross-section.
संबंधित प्रश्न
Which of the following equation shows the correct relationship between electrical unit?
1A = 1C/s or 1c= 1A/s
How many milliamperes as there in 1 ampere?
Why should the resistance of:
an ammeter be very small?
A flash of lighting carries 10 C of charge which flows for 0.01 s. What is the current? If the voltage is 10 MV, what is the energy?
If the current through a floodlamp is 5 A, what charge passed in 10 seconds?
(a) 0.5 C
(b) 2 C
(c) 5 C
(d) 50 C
An electric bulb of resistance 20 Ω and a resistance wire of 4 Ω are connected in series with a 6 V battery.
Draw the circuit diagram, and calculate:
(a) total resistance of the circuit.
(b) current through the circuit.
(c) potential difference across the electric bulb.
(d) potential difference across the resistance wire.
Consider the circuit given below:
(a) In which circuit are the lamps dimmest?
(b) In which circuit or circuits are the lamps of equal brightness to the lamps in circuit (i)?
(c) Which circuit gives out the maximum light?
Draw a circuit diagram showing two electric lamps connected in parallel together with a cell and a switch that works both lamps. Mark an â’¶ on your diagram to show where an ammeter should be placed to measure the current.
Name two effects produced by electric current.
Which effect of current is utilised in an electric light bulb?
Draw a schematic diagram of an electric circuit consisting of a battery of two cells each of 1.5 V, 5 Ω, 10 Ω and 15 Ω resistors and a plug key, all connected in series.
Tell the odd one out. Give a proper explanation.
Tick(✓) the correct choice in the following:
Which of the following quantities has the same value for all electrical
appliances connected to the ring main circuit in a house?
Define the following:
Super conductors
Find the effective resistance in the following circuit diagrams (Fig.):
Two cells each having an e.m.f. of 2 V and an internal resistance of \(2,\Omega\) are connected in series as shown in Fig. What is the current flowing through the circuit in each case?
Fig. shows a 3 pin plug with the cover removed. The electric cable
connected to the plug contains 3 wires with colour coded insulation namely brown, blue and green.
- Identify each of the colour coded wires by stating to which of the
terminals A, B or C in the diagram they should be connected. - Identify the terminal through which no current passes in normal
circumstances. - What is the purpose of the earthed wire connected to an electric
appliance like an electric heater? Describe how it works.
A 3 pin mains plug is fitted to the lead for a 1 kW electric kettle to be used on a 250 V A.C. supply. Which of the following statements is NOT correct?
(a) A 13 A fuse is the most appropriate value to use.
(b) The brown wire should be connected to the live side of the mains.
Tick (✓) the correct choice among the following :
There are 500 turns and 2000 turns in the primary and secondary coil of a
transformer respectively. If th e output voltage is 1000 V, how large is the
input voltage?
A bulb is connected to a battery of p.d. 4 V and internal resistance 2.5 Ω . A steady current of 0.5 A flows through the circuit. Calculate:
The resistance of the bulb
My mother was operating washing machine on Sunday morning. Suddenly, she saw a spark coming out of the electric board and the electric current in the house failed. An electrician was called to look into the matter. What should he have noticed.
Answer the following question.
What is the function of a galvanometer in a circuit?
______ is used to measure the electric current.
The SI unit for electric current is the coulomb.
One unit of electrical energy consumed is equal to 1000 kilowatt-hour.
Match the items in column-I to the items in column-II:
| Column - I | Column - II |
| (i) electric current | (a) volt |
| (ii) potential difference | (b) ohm meter |
| (iii) specific resistance | (c) watt |
| (iv) Electrical power | (d) joule |
| (v) electrical energy | (e) ampere |
Electric current is defined as:
The magnitude of Alternating Current (AC):
In the process of current flow through a conductor, the amount of charge passing per unit time gives:
