Thursday, July 28, 2011

Problems in Diffraction / Electrostatics

1. Consider a diffraction grating, marked at 100 lines (slits) per mm. A 632nm laser hits it. A screen is 0.75-m away from the grating. Find the following:

a. the distance between slits (in mm)
b. the distance between slits (in m)
c. the diffraction angle for n=1
d. the distance between n=0 and n=1 on the wall (which is 0.75-m away)
e. the highest order (n) that you can get from this grating and laser combination

2. Repeat the above problem for a 450nm laser.

3. Explain superposition of waves.

4. Explain diffraction.

5. Two identical charges are 0.25-m apart. If the force between them is 25-N, what is the magnitude of each charge? Is this force attractive or repulsive? Can you tell the sign of the charges?

6. Consider a 100 uC (10^-6) charge, 0.01-m away from a -300 uC charge. Find the following:

a. the force between them
b. whether or not this force is attractive or repulsive
c. the new force, if the distance is doubled
d. draw the electric field between the charges

In preparation for next class:

7. Define voltage (electric potential), current, resistance and power. Also, give the units for each.

8. What is Ohm's Law?

9. If a 9-V battery is in series with a 25-ohm resistor, what current is drawn from the battery? How much charge "flows" during one minute? What is the power radiated (in heat) by the resistor?

No comments:

Post a Comment