Question
Assume that each atom in a copper wire contributes one free electron. Estimate the number of free electrons in a copper wire having a mass of 6.4g (take the atomic weight of copper to be 64g mol-1.
✓
Answer
64 grams of copper have 1 mole
6.4 grams of copper have 0.1 mole
1 mole = No atoms
0.1 mole = (no × 0.1) atoms
= 6 × 1023 × 0.1 atoms = 6 × 1022 atoms
1 atom contributes 1 electron
6 × 1022 atoms contributes 6 × 1022 electrons.
6.4 grams of copper have 0.1 mole
1 mole = No atoms
0.1 mole = (no × 0.1) atoms
= 6 × 1023 × 0.1 atoms = 6 × 1022 atoms
1 atom contributes 1 electron
6 × 1022 atoms contributes 6 × 1022 electrons.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Suppose the spheres A and B in Exercise 1.12 have identical sizes. A third sphere of the same size but uncharged is brought in contact with the first, then brought in contact with the second, and finally removed from both. What is the new force of repulsion between A and B?
A thin but long, hollow, cylindrical tube of radius r carries a current i along its length. Find the magnitude of the magnetic field at a distance $\frac{\text{r}}{2}$ from the surface (a) inside the tube (b) outside the tube.
→Is inversion temperature always double of the neutral temperature? Does the unit of temperature have an effect in deciding this question?
Why is the mass of a nucleus always less than the sum of the masses of its constituents, neutrons and protons?
If the total number of neutrons and protons in a nuclear reaction is conserved, how then is the energy absorbed or evolved in the reaction? Explain.
Solve the previous problem if the paperweight is inverted at its place so that the spherical surface touches the paper.
A long, straight wire carrying a current of 1.0A is placed horizontally in a uniform magnetic field B = 1.0 × 10-5T pointing vertically upward figure. Find the magnitude of the resultant magnetic field at the points Pand Q, both situated at a distance of 2.0cm from the wire in the same horizontal plane.
A traffic policeman sounds a whistle to stop a car-driver approaching towards him. The car-driver does not stop and takes the plea in court that because of the Doppler shift, the frequency of the whistle reaching him might have gone beyond the audible limit of 20kHz and he did not hear it. Experiments showed that the whistle emits a sound with frequency close to 16kHz. Assuming that the claim of the driver is true, how fast was he driving the car? Take the speed of sound in air to be 330m/s. Is this speed practical with today's technology?
A tightly-wound, long solenoid carries a current of 2.00A. An electron is found to execute a uniform circular motion inside the solenoid with a frequency of 1.00 × 108 rev/s. Find the number of turns per metre in the solenoid.
Write the expression for the magnetic moment ($\overrightarrow{\text{m}}$) due to a planar square loop of side ‘l’ carrying a steady current I in a vector form. In the given figure this loop is placed in a horizontal plane near a long straight conductor carrying a steady current I1 at a distance l as shown. Give reasons to explain that the loop will experience a net force but no torque. Write the expression for this force acting on the loop.
→
You are given two circuits as shown in Fig. 14.46, which consist of NAND gates. Identify the logic operation carried out by the two circuits.
