Answer:
Choice B: The current decreases.
Explanation:
The resistance of a conductor is proportional to its length when radius and resistivity stays the same. The resistance of the longer filament will be greater than the resistance of the initial one.
For Ohmic conductors,
,
where
is the current through the conductor,
is the voltage across the conductor, and
is the resistance of the conductor.
Voltage here stays the same. Increasing the resistance of the conductor will reduce the current.
The filament might heat up over time. The filament might not be an ohmic conductor. Still, a similar trend shall exist. Resistance will be greater in the longer filament, and current will decrease.
Give the mathematical expression for coulomb's force if q1, q2 are the magnitude of charges and r is the distance between them.
F=K q1q2/r2
Answer:
9.07 x 10^-3 N/C
Explanation:
The mobility of electrons is defined as the ratio of drift velocity to the applied electric field.
Vd = 4.08 x 10^-5 m/s
Mobility = 4.5 x 10^-3 m/s
Let the electric field is E.
Mobility = Vd / E
E = Vd / mobility
E = 4.08 x 10^-5 / (4.5 x 10^-3)
E = 9.07 x 10^-3 N/C
