Advertisements
Advertisements
प्रश्न
Which instrument is used to measure electric current? How should it be connected in a circuit?
Name the device used for measuring electric current. How is it connected in a circuit?
Advertisements
उत्तर
Current is measured by an instrument called an ammeter. An ammeter is always connected in series with the circuit components because it has very low resistance. Connecting it in series ensures that the same current flows through the ammeter as through the circuit, without significantly altering the circuit’s total resistance.
संबंधित प्रश्न
In which direction do electrons flow?
Write down the formula which relates electric charge, time and electric current
What is the conventional direction of the flow of electric current? How does it differ from the direction of flow electrons?
A student made an electric circuit shown here to measure the current through two lamps.
Are the lamps in series or parallel?
(a) Are the lamps in series or parallel?
(b) The student has made a mistake in this circuit. What is the mistake?
(c) Draw a circuit diagram to show the correct way to connect the circuit. Use the proper circuit symbols in your diagram.
An electric circuit consisting of a 0.5 m long nichrome wire XY, an ammeter, a voltmeter, four cells of 1.5 V each and a plug key was set up.
Following graph was plotted between V and I values:
What would be the values of `V/I` rations when the potential difference is 0.8 V, 1.2 V and 1.6 V respectively?
What conclusion do you draw from these values?
What is the resistance of the wire?
Find the potential difference required to pass a current of 0.2 A in a wire of resistance 20Ω
State two differences between the e.m.f and terminal voltage of a cell.
Calculate the effective resistance between the points A and B in the network shown below in Figure 8.45
The following table shows the current in Amperes and potential differences in Volts.
- Find the average resistance.
- What will be the nature of the graph between the current and potential difference? (Do not draw a graph.)
- Which law will the graph prove? Explain the law.
| V (volts) | I (amp) |
| 4 | 9 |
| 5 | 11.25 |
| 6 | 13.5 |
The diagram shows two ways of connecting three lamps P, Q and R to A.C. supply of 220 V.
Define the following:
Super conductors
An electric bulb is rated at 220 V, 100 W.
- What is its resistance?
- What safe current can be passed through it?
State expression for Cells connected in series.
State the condition when it is advantageous to connect cells in parallel.
Small amounts of electrical current are measured in milliampere (mA). How many milliampere are there in 0.25 A ?
Find the odd one out.
Loudspeaker, Bar magnet/magnet, Electric motor, Microphone.
