NABTEB 2019 PHYSICS PRACTICAL VERIFIED ANSWER

_NABTEB-PHYSICS-PRACT-ANSWERS_
(2)
CLICK HERE FOR THE GRAPH

(2i)
Tabulate
S/N 1|2|3|4|5|

y(cm) 10.0|20.0|30.0|40.0|50.0|

X(cm) -30.0|60.0|30.0|24.0|21.4|

X^-1(cm^-1) -0.033|0.016|0.033|0.0416|0.046|

y^-1(cm^-1) 0.100|0.050|0.030|0.025|0.020|

(2avi)
I1 = 0.068cm^-1 , I2=0.066cm^-1
2vaii) m=1/2(I1+I2)=1/2(0.068+0.066)
=1/2*0.134=0.067
M=0.067cm^-1 , K=M^-1=1/0.067
=14.92
K=15cm

(2aviii)
– I ensured I avoided parallax error when taking readings of the meter rule by placing eye vertically above the scale
– I ensured the intensity of source of light was maintained

(2bi)
K=15cm means the focal length of the concave mirror is equal to 15cm

(2bii)
– To provide magnified image of the face
– For applying make-up or shaving
– It is used in motor vehicle head lights

(2biii)
– The image is formed on the screen
– The image is larger than the object
– Further away than the object position
– It is real and inverted
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(3)
CLICK HERE FOR THE GRAPH

(3i)
EMF=2.0V
Tabulate
K(Ω) | I(A) | I^-1(A^-1)
1.0 | 0.44 | 2.573
2.0 | 0.34 | 2.941
3.0 | 0.28 | 3.571
4.0 | 0.24 | 4.167
5.0 | 0.22 | 4.545

(3avii)
Slope (s) =ΔI^-1(A^-1)/ΔR(Ω) =4.85-2.60/4.90-1.50
=2.25/3.40 =0.662A^-1Ω^-1
Intercept (c) =2.65A^-1
3aviii) K=E*C=2*2.65=5.3A^-1V

(3aix)
– I ensured that I tightened the connection
– I avoided parallax error in reading ammeter/voltmeter

(3bi)
The value of K gives the overall resistance R(Ω)

(3bii)
Terminal p.d is the potential difference a cell in a circuit unit. When no current is flowing the terminal p.d is equal to the e.m.f of the cell. If a current is flowing then the terminal p.d of the cell will be lower than it’s EMF as some loss of energy takes place due to its internal resistance
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_COMPLETED!._
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Posted by admin on 12th May 2019.

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Categories: NABTEB