Bangladesh University Engineering and Technology
Department of Physics
Name:
Department: EEE
Answer any 10 (ten) questions
Section :
Sessional Quiz 2004
Roll No.:
Group/Batch No:
Time: 40 min
1.
What is refractive index? What is the nature of the liquid lens in determining the refractive index of liquid by Boy’s method? Write down the expression for determining the radius of curvature of the spherical surface of a convex lens.
2.
What is Malus law? If the angle between the plane of transmission of the analyzer and that of the polarizer is 30
0
, what fraction of intensity of polarized light will be transmitted through the analyzer?
3.
What is an optically active substance? Show with a suitable diagram what happens when an optically active substance is placed in a polarimeter.

4.
What do you mean by the spring constant and effective mass of a loaded spring? Show graphically how do you determine the value of spring constant and effective mass?
5.
In Newton’s rings experiment a plano-convex lens of radius of curvature 100 cm is placed on a glass plate. Light from the sodium lamp is allowed to form Newton’s rings. i) where are the
Newton’s rings formed? ii) calculate the wavelength of the light source while the square of the diameters of 5 th and 10 th rings are 0.62 cm 2 and 0.737 cm 2 respectively.
6.
In the longitudinal position of the Melde’s experiment, one end of a light piece of string is fastened to one prong of a tuning fork. The other end of the string passes over a small pulley placed at 202 cm apart from the tuning fork. A scale pan of mass 2.1 gm is hanging from the end of the string. If you need 5 gm to put on the scale pan to obtain 2 loops, calculate the frequency of the tuning fork. [mass of the 202 cm long string is 40.6 mg].

10.
7.
Define the pressure coefficient of a gas. What do you understand when the reading of the open limb is above and below the reading of the closed limb?
8.
Draw the two cooling curves one for water and other for a liquid. In the graph show the time taken by the water and the liquid to cool through the same range of temperature (say

1
to

2
). Which one has higher specific heat? Explain your answer.
9.
Why do you collect water in Searle’s experiment and how do you use this in determining the thermal conductivity of a good conductor? In this experiment, how do you protect the heat loss by convection?

11.
What are Lissajous figures? What do you understand by the time base, T
B
of an oscilloscope?
If we connect the x-channel of the oscilloscope with 23 Hz frequency source and y-channel with 69 Hz frequency source, then draw the shape of the output in the oscilloscope display.
12.
What is the unit of thermal conductivity? Why do you need to reach the steady state in the
Lee’s method experiment? Draw the temperature versus time graph. What information do we get from the graph?
13.
Write down the working formula for determining focal length of a convex lens by displacement method. Briefly explain how the auxiliary convex lens helps to determine the focal length of a concave lens.

Bangladesh University Engineering and Technology
Department of Physics
Name:
Department: CE, Ch.E & WRE
Section:
Answer any 10 (ten) questions
Sessional Quiz 2004
Roll No.:
Group/Batch No:
Time: 40 min
1.
What is Malus law? If the angle between the plane of transmission of the analyzer and that of the polarizer is 30
0
, what fraction of intensity of polarized light will be transmitted through the analyzer?
2.
What is threshold frequency of a photocathode in photoelectric effect? On what factors it depends? Show graphically how will you determine the threshold frequency and value of
Planck’s constant in the photoelectric effect experiment?
3.
Define mechanical equivalent of heat. Draw the circuit diagram for the measurement of mechanical equivalent of heat. Write down the working formula by mentioning each term.

4.
What do you understand by electromotive force (emf)? Write down Ohm’s law using proportionality relation. If cell-1 having e.m.f 10 volt requires a length 100 cm of the potentiometer wire to get null point and for cell-2 requires a length 200 cm, what is the e.m.f. of cell-2?
5.
What is an optically active substance? Show with a suitable diagram what happens when an optically active substance is placed in a polarimeter.
6.
What do you mean by the spring constant and effective mass of a loaded spring? Show graphically how do you determine the value of spring constant and effective mass?

7.
Newton’s rings experiment a plano-convex lens of radius of curvature 100 cm is placed on a glass plate. Light from the sodium lamp is allowed to form Newton’s rings. i) where are the
Newton’s rings formed? ii) calculate the wavelength of the light source while the square of the diameters of 5 th
and 10 th
rings are 0.62 cm
2
and 0.737 cm
2
respectively.
8.
In the longitudinal position of the Melde’s experiment, one end of a light piece of string is fastened to one prong of a tuning fork. The other end of the string passes over a small pulley placed at 202 cm apart from the tuning fork. A scale pan of mass 2.1 gm is hanging from the end of the string. If you need 5 gm to put on the scale pan to obtain 2 loops, calculate the frequency of the tuning fork. [mass of the 202 cm long string is 40.6 mg].
9.
Define the pressure coefficient of a gas. What do you understand when the reading of the open limb is above and below the reading of the closed limb?

10.
What are Lissajous figures? What do you understand by the time base, T
B
of an oscilloscope?
If we connect the x-channel of the oscilloscope with 23 Hz frequency source and y-channel with 69 Hz frequency source, then draw the shape of the output in the oscilloscope display.
11.
What is the unit of thermal conductivity? Why do you need to reach the steady state in the
Lee’s method experiment? Draw the temperature versus time graph. What information do we get from the graph?
12.
Write down the working formula for determining focal length of a convex lens by displacement method. Briefly explain how the auxiliary convex lens helps to determine the focal length of a concave lens.

13.
What is Seebeck effect? Consider a potentiometer’s driven e.m.f is 2 volt and it’s wire resistance is 30

. A 5000

resistance is connected in series with the potentiometer. At certain temperature, the thermo-e.m.f is found to be 3x10
-7
volt. Find the length of the potentiometer wire at which the balance point is found.
14.
What do you measure by a thermocouple? Why does the balance point remain steady during melting and freezing?

Bangladesh University Engineering and Technology
Department of Physics
Name:
Department: MME
Answer any 10 (ten) questions
Section:
Sessional Quiz 2004
Roll No.:
Group/Batch No:
Time: 40 min
1.
Define surface tension. On what factors does it depend? Write down the working formula for the calculation of surface tension of water.
2.
What is refractive index? What is the nature of the liquid lens in determining the refractive index of liquid by Boy’s method? Write down the expression for determining the radius of curvature of the spherical surface of a convex lens.
3.
What is temperature co-efficient of resistance? Why does the resistance of metals varies with temperature? Write the name of a substance whose resistance decreases with temperature.

4.
What is Malus law? If the angle between the plane of transmission of the analyzer and that of the polarizer is 30
0
, what fraction of intensity of polarized light will be transmitted through the analyzer?
5.
What is threshold frequency of a photocathode in photoelectric effect? On what factors it depends? Show graphically how will you determine the threshold frequency and value of
Planck’s constant in the photoelectric effect experiment?
6.
Define mechanical equivalent of heat. Draw the circuit diagram for the measurement of mechanical equivalent of heat. Write down the working formula by mentioning each term.

7.
What do you understand by electromotive force (emf)? Write down Ohm’s law using proportionality relation. If cell-1 having e.m.f 10 volt requires a length 100 cm of the potentiometer wire to get null point and for cell-2 requires a length 200 cm, what is the e.m.f. of cell-2?
8.
What is an optically active substance? Show with a suitable diagram what happens when an optically active substance is placed in a polarimeter.
9.
In Newton’s rings experiment a plano-convex lens of radius of curvature 100 cm is placed on a glass plate. Light from the sodium lamp is allowed to form Newton’s rings. i) where are the
Newton’s rings formed? ii) calculate the wavelength of the light source while the square of the diameters of 5 th
and 10 th
rings are 0.62 cm
2
and 0.737 cm
2
respectively.

10.
In the longitudinal position of the Melde’s experiment, one end of a light piece of string is fastened to one prong of a tuning fork. The other end of the string passes over a small pulley placed at 202 cm apart from the tuning fork. A scale pan of mass 2.1 gm is hanging from the end of the string. If you need 5 gm to put on the scale pan to obtain 2 loops, calculate the frequency of the tuning fork. [mass of the 202 cm long string is 40.6 mg].
11.
What are Lissajous figures? What do you understand by the time base, T
B
of an oscilloscope?
If we connect the x-channel of the oscilloscope with 23 Hz frequency source and y-channel with 69 Hz frequency source, then draw the shape of the output in the oscilloscope display.
12.
Write down the working formula for determining focal length of a convex lens by displacement method. Briefly explain how the auxiliary convex lens helps to determine the focal length of a concave lens.

13.
What is Seebeck effect? Consider a potentiometer’s driven e.m.f is 2 volt and it’s wire resistance is 30

. A 5000

resistance is connected in series with the potentiometer. At certain temperature, the thermo-e.m.f is found to be 3x10
-7
volt. Find the length of the potentiometer wire at which the balance point is found.
14.
What do you measure by a thermocouple? Why does the balance point remain steady during melting and freezing?