an electron moves with constant speed at right angles to a uniform magnetic flux, if the flux density were doubled, the force on the electron would be
A) unaffected
B) reduced to one month
C) halved
D) doubled
E) quadrupled
force=q*v*B, right?
i dno that's y m posting it here
F=qvB,
B1=2•B
F1 = qvB1 =qv2B =2F
D) doubled
To determine the effect of doubling the flux density on the force acting on an electron moving at right angles to a uniform magnetic flux, we can use the formula for the magnetic force experienced by a moving charge:
\[ F = q \cdot v \cdot B \cdot \sin\theta \]
where:
- F is the magnetic force
- q is the charge of the particle (electron)
- v is the velocity of the electron
- B is the magnetic field (flux density)
- θ is the angle between the velocity vector and the magnetic field vector
In this case, since the electron moves at right angles (90°) to the uniform magnetic flux, the value of θ is 90°, and the equation simplifies to:
\[ F = q \cdot v \cdot B \]
If we consider all other variables (charge and velocity) to remain constant, then only the flux density (B) changes. Doubling the flux density (B) means multiplying it by 2.
Now let's examine the effect on the force:
\[ F_{new} = q \cdot v \cdot (2B) = 2(q \cdot v \cdot B) = 2F \]
Comparing the new force (F_new) to the original force (F), we can see that the new force is twice as large as the original force. Therefore, the correct choice is:
D) The force on the electron is doubled when the flux density is doubled.