Term
| What is the electric field E at a distance d=4cm from a positive charge of Q=10^-4C on the tip of a glass rod? |
|
Definition
| E=kQ/d^2 so E=5.6x10^8 N/C which is 5.6x10^8 V/m. The direction of the electric field is away from the glass rod. |
|
|
Term
| In electric field E of 300 V/m=300N/C, what is the force F on a charge of 10^-4 C? |
|
Definition
|
|
Term
| The electric field E 1m away from a point charge has magnitude 24,300 V/m. What is its magnitude 3m away? What does the electric field E 1m away from the source become when every charge in the system is made 1/3 as large? |
|
Definition
| Because E is proportional to 1/d^2, the field 3m away is 1/9 as large as the field 1m away, 2700V/m. If the charge is reduced to 1/3 its original value, the field everywhere becomes 1/3 as large: 8100 V/m at 1m and 900V/m at 3m. |
|
|
Term
| Two metal plates are separated by 3cm and have length and width much greater than their separation. The potential difference between them is 30,000V. What is the magnitude of the electric field E halfway between the two plates? What is the magnitude of the electric field E outside of them? |
|
Definition
| Between the plates deltaV=Ed so E=10^6V/m. Outside the region, the field is much smaller. |
|
|
