Physics review Practice problems 1. A double slit interference pattern is observed on a screen 2.0 m behind 2 slits spaced 0.5 mm apart. From the center of one particular fringe to 9 th bright fringe is 1.6 cm. find the wavelength of the light? 2. A thin film of material with an index of refraction n = 1.28 is coated onto plastic lens (n=1.55). it is desired to have destructive interference for wavelength 550nm. What is the thinnest film required to achieve this?
3. A laser beam is aimed at 1.0 cm thick sheet of glass at an angle of 30 above glass. a. What is laser s direction in glass? b. What is laser s direction in air? c. What is laser s direction in other side of glass? 4. A stamp collector uses a converging magnifying glass that sirs 2 cm above the stamp creating a virtual image. The magnification is 4. What is the focal length of the lens? 5. A concave mirror has a focal length of 2.4 cm. where should a candle be placed so that image is inverted and twice as large as the object?
6. Two 10 nc and 20 nc charged particles are 3.0 cm apart on x-axis. What is the net force on a +0.5 nc charge midway between them? (Hint: draw a diagram first) 7. What are the strength and direction of electric field 2.0 mm from a proton and electron? (Hint if q<0, towards q, if q>0, away from q) 8. A proton moves through an electric potential created by a number of source charges. Its speed is 3.0 x 10 5 m/s at a point where the potential is 1200 V. What will be the proton s speed a short time later when it reaches a point where the potential is -200 V?
9. A point P is located 6.0 cm from a 3.0 nc charge and 4.0 cm away from a -1.0 nc charge. The two charges are 3.0 cm apart from each other. Find the net potential of both the charged. 10. A 1.0 mf capacitor is connected to 1.5 V battery. What is the charge on the capacitor? 11. A 20 cm long with a diameter of 0.4 mm wire is connected to a 1.5 V battery, what is the current in the wire? 12. A filament is connected to 120 V of electric outlet, a 60 W bulb carries a current of 0.50 A. Find the resistance of the thin wire.
13. Find the total resistance, total current, current and voltage drops in individual resistor
14. 15. Find the capacitance equivalence of the following circuit.
16. The capacitor is fully charged. The switch is changed to position b at t = 0. What is the current in the circuit immediately after the switch is closed? What is the current in the circuit 25 µs later? Example 23.11 Source: College Physics II textbook 17. Draw a circuit diagram for this figure.
18. A typical solenoid has a length of 1 m and diameter of 1 m. the field inside the solenoid is 4 T. how many turns of wire must the solenoid have to produce this field if the largest current the wire can carry is 150 A? 19. A proton is moving to the right above a horizontal wire that carries a current to the right. What is the direction of the magnetic force on the proton? 20. An electron. Is moving to the left in a magnetic field that points upward. What is the direction of magnetic force? (Hint: draw the diagram first) 21. The sun emits charged particles that move towards earth at a speed of 500 km/s. at this point, the earth s field is 5.0 x 10-5 T directed parallel to earth s surface. What are the direction and magnitude of force on the proton?
22. The earth s magnetic field is 50µT tipped at an angle of 60 below horizontal. A 10 cm diameter circular loop of wire sits flat on table. What is the magnetic flux through the loop? 23. What is the direction of induced current in the coil if the a. Magnet moves towards coil b. Magnet moves away from the coil c. Magnet remains stationary
24. What is the photon energy in ev for germicidal lamps that use wavelength 254 nm? (1 ev = 1.60 x 10-19 J) 25. A hot wire dissipates 680 W when plugged into a 120 V outlet. a. What is the wire s resistance? b. What are the rms and peak current through the wire? 26. An AM radio antenna picks up a 2000 khz signal with a peak voltage of 5.0 mv. The tuning circuit consists of a 60 µh inductor in series with capacitor. The inductor coil has a resistance of 0.25 ohms. a. To what value should the capacitor be turned to listen to this radio station? b. A stronger station at 2050 khz produces a 10 mv antenna signal. What is the current at this frequency when the radio is tuned to 2000 khz?