Question
An electron is not deflected while passing through any field. Is it possible that there is no magnetic field present at that place? Explain.
✓
Answer
Exerting force in magnetic field on a moving electron with velocity $\vec{v}$
$\overrightarrow{ F }=-e(\vec{v} \times \overrightarrow{ B })$
or $\overrightarrow{ F }=-e v B \sin \theta$
If $\theta=0^{\circ}$ or $180^{\circ}$, the magnitude of force F will be zero. Hence, an electron will not be deflected if it moves parallel or opposite to the direction. So, we cannot say that magnetic field is absent.
$\overrightarrow{ F }=-e(\vec{v} \times \overrightarrow{ B })$
or $\overrightarrow{ F }=-e v B \sin \theta$
If $\theta=0^{\circ}$ or $180^{\circ}$, the magnitude of force F will be zero. Hence, an electron will not be deflected if it moves parallel or opposite to the direction. So, we cannot say that magnetic field is absent.
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
Can a plane mirror ever form a real image?
A hollow sphere filled with water is used as the bob of a pendulum. Assume that the equation for simple pendulum is valid with the distance between the point of suspension and centre of mass of the bob acting as the effective length of the pendulum. If water slowly leaks out of the bob, how will the time period vary?
- Find the first excitation potential of $He^+ \text{ion}.$
- Find the ionization potential of $Li^{++ } \text{ion}.$
In the figure shown, calculate the total flux of the electrostatic field through the spheres $S_1$ and $S_2.$ The wire $AB$ shown here has a linear charge density $\lambda$ given by $\lambda=\text{kx}$ where $x$ is distance measured along the wire, from the end $A.$
→What will be the radius of a conducting sphere having electric capacitance of one Farad?
Two stable isotopes of lithium $^6_3\text{Li }\text{ and }\ ^7_3\text{Li}$ have respective abundances of 7.5% and 92.5%. These isotopes have masses 6.01512 u and 7.01600 u, respectively. Find the atomic mass of lithium.
→A block of mass m having a charge q is placed on a smooth horizontal table and is connected to a wall through an unstressed spring of spring constant k as shown in figure. A horizontal electric field E parallel to the spring is switched on. Find the amplitude of the resulting SHM of the block.
Two capacitors of capacitance 6 μF an 12 μF are connected in series with a battery. The voltage across the 6 capacitor is 2 V. Compute the total battery voltage.
A heavy mass m is hanging from a string in equilibrium without breaking it. When this same mass is set into oscillation, the string breaks. Explain.
What is electrostatic shielding? How is this property used in actual practice? Is the potential in the cavity of a charged conductor zero?