Al- Azhar University
Laboratory Technical
Institute
Second year
Time : 20 minutes
Faculty of Science
Physic Department
Name:
Question [1]: (✔ ) or (✖ ) and correct the wrong answer.
[4 marks]
1- In Lee’s experiment if the thickness of wood increased to twice, the coe cient of
thermal conductivity of wood would increase to twice. (
)
2- In the photoelectric e ect experiment the energy of electrons emitted from a
metal depends on the frequency of the incident light .
(
)
3- If the angle of incidence is bigger than the critical angle, there is no a refraction
angle.
(
)
4 - In Stefan’s experiment the rate of lost energy by conduction is bigger than that
that of radiation .
(
)
Question [2]: Complete
[1 mark]
1- In the polarimeter, the concentration of a sugar solution is directly proportional to
the rotation angle produced and the constant of proportionality is called ………...….
2- The work function is …………………………………………….……….......................
Question [3]: What’s the unit of :
[2 marks]
1- The electrical energy ………………………………
2- The thermal energy ………………………………..
3- Power……………………..…
4- The refractive index…….......................…
Question [4] : Draw the electrical circuit of Stefan’s experiment.
[1 mark]
ffi
ff
Look back ->
ff
Question [5]: Draw the characteristic curve between the potential and the current
for a photocell at di erent distances from the light source d= 8 cm and d = 22 cm.
Show all information on the graph. And explain your results.
[2 marks]