Question:
An electron is moving along positive x direction in xy plane, magnetic field points in negative z direction, then the force due to magnetic field on electron points in the direction
An electron is moving along positive x direction in xy plane, magnetic field points in negative z direction, then the force due to magnetic field on electron points in the direction
Updated On: Nov 21, 2025
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The Correct Option is B
Solution and Explanation
The power dissipated across a resistor is given by the formula:
\[
P = \frac{V^2}{R},
\]
where \( P \) is the power, \( V \) is the potential difference, and \( R \) is the resistance.
If the potential difference \( V \) is doubled, the new potential difference is \( 2V \). The new power \( P' \) is:
\[
P' = \frac{(2V)^2}{R} = \frac{4V^2}{R} = 4P.
\]
Thus, the power dissipated becomes four times when the potential difference is doubled.
Hence, the correct answer is \( \boxed{(2)} \).
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Concepts Used:
Biot Savart Law
Biot-Savart’s law is an equation that gives the magnetic field produced due to a current-carrying segment. This segment is taken as a vector quantity known as the current element. In other words, Biot-Savart Law states that if a current carrying conductor of length dl produces a magnetic field dB, the force on another similar current-carrying conductor depends upon the size, orientation and length of the first current carrying element.
The equation of Biot-Savart law is given by,
\(dB = \frac{\mu_0}{4\pi} \frac{Idl sin \theta}{r^2}\)
Application of Biot Savart law
- Biot Savart law is used to evaluate magnetic response at the molecular or atomic level.
- It is used to assess the velocity in aerodynamic theory induced by the vortex line.
Importance of Biot-Savart Law
- Biot-Savart Law is exactly similar to Coulomb's law in electrostatics.
- Biot-Savart Law is relevant for very small conductors to carry current,
- For symmetrical current distribution, Biot-Savart Law is applicable.
For detailed derivation on Biot Savart Law, read more.