## NOUN Past Questions: PHY 391 - Laboratory Physics

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### NOUN Past Questions: PHY 391 - Laboratory Physics

COURSE CODE: PHY 391
COURSE TITLE: LABORATORY PHYSICS

Time: 2hrs

1. A trolley loaded with four 50 g masses and attachedto a 50 g mass carrier by meansof a string in an experimentto investigate the relationshipbetweenforce, mass and acceleration. The trolley is releasedand after severalruns, the mean accelerationis calculated.
The experimentis repeated4times,with one massfrom the trolleybeing transferredto the mass carrier each time. This varies the force acting on the system whilekeeping the total mass of the system constant. Note that the term "system" refers tothe trolley + masseson trolley + hangingmasses.The results are shown in the table below.

(a) On the graph paper provided, plot the force on the system versus the meanacceleration. Draw a straight line of best fit.
(b) Calculate the slope of your graph.
(c) What does the slope of your graph represent?
(d) Use your graph to determine the mass of the unloaded trolley.
(e) Explain why your graph does not pass through the origin.
(f) Does the "Force on System" shown in the table represent the applied force or
the net force acting on the system? Explain.
(g) Determine the size (if any) of the frictional resistance between the trolley and
the bench.

2. A ball of mass 0.25kg is projected vertically upwards from te ground with an initial velocity of 30ms-1. The acceleration of free fall is 10ms-2, but air resistance cannot be neglected. The table below shows the variation with time t of the velocity v of the ball for the upward part of the motion.

t(s) 0 0.5 1.0 1.5 2.0
v(m/s) 30 20 12 5.5 0
Plot the graph of velocity against time.
State what the area under the curve represents.
Estimate the maximum height reached by the ball.
Determine for the ball at t = 1.0s (i) the acceleration (ii)magnitude of the force air resistance.
Use the graph to explain without any further calculations tat the force of air resistance is decreasing in magnitude as the ball moves upward.

3. A student uses the circuit shown in Fig. 5.1 to determine the e.m.f.. E and the internal
resistance r of a cell.

The variable resistor can be set to known values R. The voltmeter measures thepotential difference V across the resistor. This is the same as the terminal potentialdifference of the cell. The student takes a set of values of V corresponding to differentvalues of R. He records the results in Table below.

The student plans to use the equation: 1/V=r/ER+1/Eto use a graphical method to obtain the values of E and r.
(a) (i) What graph should be plotted so as to give a straight line from which E and rcan be obtained? State the horizontal and vertical axes. (ii) Show how the values of E and r are related to the gradient and intercept ofthe graph in (i).
(b) (i) Label the third and fourth columns of Table with the quantities thatshould be calculated for the x- and y-axes for the graph in (a)(i). Includeappropriate units. (ii) Calculate the values for the third and fourth columns of the Table. Recordthem in Table. (iii) Draw the graph of the processed data in the Table.Label the axes and choose suitable scales. Plot the points and draw the beststraight line through them.
(c) (i) Measure the gradient of the graph. Include an appropriate unit.(ii) Measure the y-intercept of the graph. Include an appropriate unit.(iii) Hence calculate the values of E and r.
(d) The voltmeter used in Fig. 5.1 must have a very high resistance.(i) Explain why this is necessary.(ii) The student has used an unsuitable spacing for the values of resistance R.

4. The table below shows the values of dynamic pressure, q, measured by a Pitot-static tube
when an aircraft is moving with velocity v (Pitot-static tubes are used on aircraft as speedometers). The dynamic pressure, q is related to the velocity of the aircraft by the equation, =1/2 ρv^n.

(i) Calculate values of log q and log v and insert them into the remaining
columns of the Table.
(ii) Plot a suitable linear graph from which you will be able toobtain a value for n. Draw the best straight line through the points.
(iii) Use your graph to calculate a value for n.
(iv) Use Equation to calculate a value for ñ, the density of air at the cruisingheight of this aircraft using the value of n obtained in (iii).

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### Re: NOUN Past Questions: PHY 391 - Laboratory Physics

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COURSE CODE:PHY391
COURSE TITLE: LABORATORY PHYSICS II
COURSE UNIT: 2 units
TIME: 2 hours
Q1. (a). State the Reciprocity Theorem. (3 Marks)
(b). With the aid of circuit diagrams differentiate between 3-Terminal and 4-Terminal
Network. ( 6 Marks)
c). With the aid of a diagram explain the steps to be taken when carrying out the calibration
of a Thermistor. ( 8 ½ Marks)
Q2. (a). State the Thevenin’s Theorem. 4marks
(b).
S. No. Load Resistance (RL) ohms Output Voltage (V0) volts V02 volts Power Transfer
P= V02/ RL
1
2
3
4
5
6
7
8 2
4
6
10
14
18
22
26 20
40
60
100
140
180
220
260

i. Complete the Table 2Marks
ii. Plot a graph of RL against V024Marks
iii. Calculate the slope 2Marks
iv. What is the meaning of the slope 2Marks

c) Three capacitors of capacitance C1=2μ, C=2μ and C=3μ are connected in Parallel, calculate the Effective Capacitance of the circuit. 3 ½ Marks

3a. State Ohm’s Law 3marks
b. Define the following
i. Mesh 3marks
ii. Node 3marks
iii. Active Network 3marks
iv Passive Network 3marks
c. State Superposition Theorem 3 ½ Marks

4. a. List 3 Apparatus used in Spectral Analysis Using Grating Spectrometer. 6marks
b. Define Ripple Factor. 4 marks
c. State the Law of Reflection of light 4marks
d. Explain the term ‘’critical angle’’ 3 ½ marks

5. a. Differentiate between a Converging lens and a Diverging lens.9marks
b. Define Resistivity of a wire. 3 ½ marks
c. Define Common Mode Rejection Ratio (CMRR). 4 marks

6.a. With the aid of a diagram explain the Energy Band Diagram10 marks
b. Define the following:
i. Network Branch 2 ½ marks
ii. Couple 2 ½ marks
c. what is the use of a Polaroid? 2 ½ marks

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MichaelTop
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Clicking that link always just takes me to the first post of the thread. Is there any way to fix this?
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### Re: View first unread post

MichaelTop wrote:
Sun Jul 15, 2018 4:24 am
Clicking that link always just takes me to the first post of the thread. Is there any way to fix this?