Answer:

Explanation:
Force on a current carrying rod due to magnetic field is given as

here we know that
current in the rod


now magnetic force is balanced by the weight of the rod
so we will have



Speed = Distance/ Time
Speed = 400 / 4
Speed = 100 km/hr.
100 km per hour.
So we want to know what changes inside the multimeter when we change the voltage range from 200 V to 20 V, by what factor and does it increase or decrease. What we want when trying to measure the voltage with a multimeter is that a minimal current passes trough the mulitmeter so when we change the voltage range, we decrease the resistance by a factor of 10 because the voltage is decreased by a factor of 10.