Answer:
Explanation:
The two major defects of simple electric cells causes current supplied to be for short time. These defects are: polarization and local action.
a. Polarization: This is a defect caused by an accumulation of hydrogen bubbles at the positive electrode of the cell. It can be prevented by the use of vent, using a hydrogen absorbing material or the use of a depolarizer.
b. Local Action: This is the gradual wearing away of the electrode due to impurities in the zinc plate. It can be controlled by the amalgamation of the zinc plate before it is used.
The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet that needs no power, an electromagnet requires a continuous supply of current to maintain the magnetic field.
Answer:
Gravitational field strength =weight/mass
Explanation:
14.8N/4.0kg
3.7N/kg
Answer:
Balanced force
Explanation:
Balanced Forces, When forces are in balance, acceleration is zero. Velocity is constant and there is no net or unbalanced force. ... Although friction is acting on the person, there is no change in velocity and friction is not a net force in this case. Friction is only a net force if it changes the velocity of a mass.
Time= 20 minutes= 20*60=1200 s
Charge=current*time=12*1200=14400 C
