## Physics 2011 | Study Mode

Question 1
A
the inside of the lift is air tight
B
the lift is in vacuum
C
there is no reaction from the floor of the lift
D
there is no gravitational pull on the man in the lift
Explanation.
The resultant force acting on the man is given by w = mg - R
Mg - mg = 0
The man feels weightless because the reaction, R is equal to the weight mg

Question 2
A
X and Y will be 500 m from each other
B
Y will be 500 m ahead of X
C
X will be 500 m ahead of Y
D
X and Y both be 500 m from the poin of throw
Explanation.
v2 = U2 - 2G s
0 = 1002 - 2 x 10 x s = 10000 - 20s
s = (10000)/20 = 500m
Which is independent of mass.the two bodies where acted upon by the same retarding force of gravity which is independent of mass of the body; therefore both will be 500 m from the point of throw.

Question 3
A
90 m
B
30 m
C
45 m
D
60 m
Explanation.
S = (1)/2gt2
S = (1)/2 x (10)/1 x 32 =5 x 9 = 45 m

Question 4
A
25 N
B
100 N
C
50 N
D
40 N
Explanation.
Centripetal force,
F = $$\frac{mv^2}{r}$$
= $$\frac{2 \times 10^2}{4}$$
= $$\frac{200}{4}$$= 50N

Question 5
A
600 J
B
150J
C
300 J
D
450 J
Explanation.
K e just before hitting the gound
= P e at the maximum height (conservation of mechanical energy)
K e = P e = mgh = 1.5 x 10 x 20
= 300 J

Question 6
A
remain at the same level irrespective of whether the liquid wet the glass or not
B
fall below the liquid level if the liquid wets the glass
C
falls below the liquid level if the liquid does not wet the glass
D
rise above the liquid level if the liquid does not wet the glass
Explanation.
The liquid will rise up the capillary if it wets glass and falls below its wets glass and falls below its initial level if it does not wet glass

Question 7
A
50 N
B
520 N
C
220 N
D
80 N
Explanation.
upthrust = weight in air - weight in liquid = 30 x 10 - 22 x 10 = 300 - 220 = 80 N

Question 8
A
0.12 cm3
B
4.00 cm3
C
1.20 cm3
D
0.40 cm3
E
no correct option
Explanation.
increase in volume, DV = RV1 = 3 Vsub>1 D
= 3 x 2.0 X 10-5 x 40 x (90 - 30)
= 6 x 10-5 x 40 x 60
0.144 cm3
No correct option

Question 9
A
2. 0 x 10-5
B
7.0 x 10-3
C
7.0 x 10-4
D
2.2 x 10-4
Explanation.
Young modules = $$\frac{\text{Tensile stress}}{\text{Tensile strain}}$$

= $$1.1 \times 10^11 = \frac{7.7 \times 10^7}{\text{Tensile Strain}}$$

Tensile strain = $$\frac{7.7 \times 10^7}{1.1 \times 10^11}$$

= $$7.0 \times 10^{7-11} = 7.0 \times 10^{-4}$$

Question 10
A
I and II
B
I, II,III and IV
C
I, III and IV
D
II, III and IV
Explanation.
A good thermometric liquid should not have a high thermal capacity so that the themperetue of the body being measured will not be affected
II, III and IV are qualities of a good thermometer

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