A solution of sodium chloride discharges 6.1 × 10 16 Na + ions and 4.6 × 10 16 Cl − ions in 2 s . Find the current passing through the solution.

Amount of current is due to both cations and anions I = I cations + I anions I = I cations + I anions = n + + n − e t I = 6.1 × 10 16 + 4.6 × 10 16 × 1.6 × 10 − 19 2 I = 8.56 × 10 − 3 A .

A solution of sodium chloride discharges 6.1 × 10 16 Na + ions and 4.6 × 10 16 Cl − ions in 2 s . Find the current passing through the solution.

Amount of current is due to both cations and anions I = I cations + I anions I = I cations + I anions = n + + n − e t I = 6.1 × 10 16 + 4.6 × 10 16 × 1.6 × 10 − 19 2 I = 8.56 × 10 − 3 A .

An electron moves in a circular orbit of radius 10 cm with a constant speed of 4 . 0 × 10 6 ms − 1 . Determine the electric current at a point on the orbit.

Given that, Circular orbit of radius, r = 10 cm Speed of electron, v = 4.0 × 10 6 ms − 1 Expression for time period, T = 2 π r v ∴ v = 1 T = 4 × 10 6 2 π × 0.10 s − 1 I = v × e = 4 × 10 6 × 1.6 × 10 − 19 2 π × 0.10 = 1.02 × 10 − 12 A .

A metal wire of specific resistance 64 × 10 − 8 Ωm and length 1.98 m has a resistance of 7 Ω . Find its radius.

Given that, Specific resistance of the wire is 64 × 10 − 8 Ω m length of the wire is 1.98 m resistance of the metal wire is 7 Ω Expression for resistance of a metal wire is, R = ρ l A Let’s assume radius of the copper wire is r As R = ρ l A = ρ l π r 2 ∴ r 2 = ρ l π R = 64 × 10 − 8 × 1.98 × 7 22 × 7 = 5.76 × 10 − 8 m 2 or r = 2.4 × 10 − 4 m

E M B I B E

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 3

EASY

12th CBSE

IMPORTANT

Earn 100

A solution of sodium chloride discharges $6.1 \times 10^{16} {Na}^{+}$ ions and $4.6 \times 10^{16} {Cl}^{-}$ ions in $2 s$ . Find the current passing through the solution.

Important Questions on Current Electricity

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 4

An electric current of

2.0 μA

exists in a discharge tube. How much charge flows across a cross-section of the tube in

5

minutes?

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 5

In a hydrogen atom, the electron makes about

0.6 \times 10^{16}

revolutions per second around the nucleus. Determine the average current at any point on the orbit of the electron.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 6

An electron moves in a circular orbit of radius

10 cm

with a constant speed of

4.0 \times 10^{6} {ms}^{- 1}

. Determine the electric current at a point on the orbit.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 7

In a hydrogen discharge tube, the number of protons drifting across a cross-section per second is

1.1 \times 10^{18}

, while the number of electrons drifting in the opposite direction across another cross-section is

3.1 \times 10^{18}

per second. Find the current flowing in the tube.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 1

A voltage of

30 V

is applied across a color-coded carbon resistor with first, second and third rings of blue, black and yellow colors. What is the current flowing through the resistor?

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 2

A potential difference of