Question

1 A repelling force must occur between two charged objects under which conditions? 

a. charges are of unlike signs b. charges are of like signs c. charges are of equal magnitude  d.charges are of unequal magnitude 

2 Two point charges are 4 cm apart. They are moved to a new separation of 2 cm. By what factor does the electric force between them change? 

a.2 b. 1/2 c.4 d. 1/4  

3. By mapping the equipotential lines, you can draw 

a. the charge b. the electric field lines d. the magnetic field lines c. nothing 

4. In which of the following experiments a galvanometer was NOT used? 

a. mapping of the electric field b. study of a source of emf and terminal voltage c. the Wheatstone bridge method  d. capacitance and capacitors  

5 When a dielectric was inserted between the plates of the capacitor, the capacitance 

a. increased b. decreased c. was zero d. wasn't affected 

6. When verifying Ohm's law, you found that the electric current was a function of 

 a. capacitance b. voltage c. milliamps d. time 

7. When verifying the heating effect of an electric current, every 60 seconds, you measured the 

a. temperature b. time c. resistance d. current  

8. Fig. 1 is a Wheatstone bridge circuit. No current flows through the galvanometer. You find Rx is 

a. 1Ω b. 5Ω c. 25Ω d. 144Ω

9 When verifying Ohm's law, you plotted a current-voltage graph based on the measured data for an unknown resistor, as shown in Fig. 2. Its resistance is estimated to be 

a. 0.00006 Ω b. 0.00142 Ω c. 16.7 kΩ d. 704 Ω

10. Which experiment verified conservation of energy? 

a. Ohm's law b. the heating effect of an electric current d. the Wheatstone bridge method  c.capacitance and capacitors 

11. Which experiment dealt with the right hand rule? 

a. force on a current carrying wire in an external magnetic field 

b. the heating effect of an electric current 

c. emf and terminal voltage 

d. mirrors and lenses 

12. When verifying Kirchhoffs rules, you measured 

a. temperature c. time d current b. resistance  

13. When verifying Kirchhoffs rules, how many variable resistors did you use to set up the circuit? 

a. 4 b. 3  c.2 d. 1

14. A 20 cm wire carrying a current of 2.00 A is placed in a uniform magnetic field of 0.20 T. If the wire makes an angle of 30 degrees with the vector of magnetic field, the magnitude of the force on the wire is

 a. 0.08 N/C b. 0.08 N c. 0.04 N/C d. 0.04 N 

15. When measuring e/m for electrons the radius of the electron beam varied as the 

a. accelerating voltage  b. resistance c. power d. temperature 

16. When measuring e/m for electrons, the electron beam was deflected in a 

a. straight line b. circle  c. trajectory d. helix 

17. A light ray passes from glass lens into air. If the critical angle is measured to be 39°, then the index of refraction of the glass lens is 

a. 0.63 b. 1.33 c. 1.59 d. 1.50  

18. The incident light ray enters water from air with an angle of incidence θ=65°. The index of refraction of water is 1.33. The angles of reflection and refraction are, respectively, 

a. 25°: 43° b. 65°; 43° c. 250°;49° d. 65°:49° 

19. An object is placed 30 cm in front of a concave spherical mirror with a focal length of 20 cm. Which of the following is true? 

a. The image is 60cm behind the mirror, inverted b. The image is 60cm behind the mirror, upright. c. The image is 60cm in front of the mirror, inverted. d. The image is 60cm in front of the mirror, upright. 

20. The first bright fringe of a diffraction grating of 600 ruling/mm is found at the angle of 15°. Find the wavelength of the laser source. 

a. 3.9x10^-4m b. 4.3 x10^-2m c. 4.3 x 10^-7m d. 3.9 x10^-5m

Answer 1

1) repelling force occurs when both charges are like signs option b .unlike charges attract while like charges repel

2) Force is inversely proportional t square of distance F = kq1q2/r^2 so decreasing r increases F since r became 1/2 F becomes new F become =kq1q2/(r/2)^2 = 4kq1q2/r^2 F becomes 4 times option c

Answer 2

3) The correct option is (b)- the electric field lines.

As the equipotential lines are trace lines with equal voltage and these lines are always perpendicular to electric field lines so we can draw the electric field lines by drawing the electric potential lines.

Answer 3

4)

The galvanometer is not used in capacitance and capacitor

5)

When the dielectric is inserted the capacitance is increased.