Advertisements
Advertisements
Question
Calculate the number of electrons constituting one coulomb of charge.
Advertisements
Solution
One electron possesses a charge of 1.6 × 10-19C, i.e., 1.6 × 10-19C of charge is contained in 1 electron.
∴ 1 C of charge is contained in `1/(1.6 xx 10^(-19))`
= 6.25 × 1018
= 6 × 1018
Therefore, 6 × 1018 electrons constitute one coulomb of charge.
APPEARS IN
RELATED QUESTIONS
Fill in the folloing blank with suitable words:
A current is a flow of ............... .For this to happen there must be a ............... circuit.
Which type of circuit, series or parallel, is preferred while connecting a large number of bulbs:
(a) for decorating a hotel building from outside?
Draw a circuit diagram showing two lamps, one cell and a switch connected in series.
How can you change the brightness of the lamp?
Which effect of current is utilised in an electric light bulb?
Define the term resistivity.
A switch must be connected in ______.
The following circuit diagram shows three resistors 2 Ω, 4 Ω and R Ω connected to a battery of e.m.f 2V and internal resistance 3 Ω. If the main current of 0.25 A flows through the circuit, find:
- the p.d. across the 4 Ω resistors,
- the p.d. across the internal resistance of the cell,
- the p.d. across the R Ω or 2 Ω resistors, and
- the value of R.
Define the following:
Super conductors
Complete the following table. The first answer has been given as an example.
| Quantity | Unit | |
| (a) | Electrical potential | volt |
| (b) | Resistance | ........ |
| (c) | Power | ........ |
| (d) | Energy | ........ |
| (e) | Resistivity | ........ |
Electrical appliances have voltage and power ratings as listed below. Which
has the larger working resistance?
| Appliances | Voltage (V) | Power (W) |
| (a) Washing machine | 250 | 3000 |
| ( b) Television | 240 | 160 |
| (c)240 | 240 | 1500 |
| ( d) Hair curler | 250 | 20 |
| ( e) Car head lamp | 12 | 36 |
Tick (✓) the correct choice among the following :
Which of the following changes would enable a millimeter to be used as a
direct current ammeter reading upto 1 A?
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?
What determines the direction of flow of electrons between two charged conductors kept in contact?
Water : pipe :: Electric current : ______.
The flow of electric charge per unit time is called potential difference.
Problems for practice:
If 3A current flows through a circuit, then convert the current in terms of a milliampere.
