## Physics 2009 Study Mode

Try this quiz in CBT Mode

Question 21
A
10 cm in front of the mirror.
B
5 cm in front of the mirror
C
10 cm behind the mirror
D
5 cm behind the mirror
Explanation.
u = 5 cm , f = 10 cm, v = ?
(1)/v + (1)/u = (1)/f
(1)/v + (1)/5 = (1)/10
= (1)/v = (1)/10 = (1)/5 = (1 - 2)/10 = (1)/10
v = - 10 cm
The image is 10 cm behind the mirror

Question 22
A
4. 0 cm
B
3. 0 cm
C
12.0 cm
D
9.0 cm
Explanation.
f = -12 cm, v = - 6 cm
(1)/v + (1)/u =(1)/f
(1)/-6 + (1)/u = (1)/-12
(1)/u = (1)/-12 + (1)/6 = (1 + 2)/12 = (1)/12
u = 12 cm

Question 23
A
48.6
B
22.5
C
41.5
D
45
Explanation.
Sin c = (1)/n
= (1)/1.51 = 0.6622
c = sin +0.6622 = 41.47

Question 24
A
x is same as in y
B
x and y is same as in vacuum
C
x is higher than in y
D
y is higher than in x
Explanation.
Since 1.51, the refractive index of X is greater than 1.33, the refractive index of y, the speed of light in y is higher than that in X

Question 25
A
interference
B
diffraction
C
accomodation
D
superposition
Explanation.
The leaves collapse as the position charges on the rod neutralize the negative charges on the electroscope

Question 26
A
blue
B
orange
C
red
D
green
Explanation.
Primary colours are red, blue and green
orange is a secondary colour

Question 27
A
close up
B
become positively charged
C
become negatively charged
D
open further
Explanation.
The leaves collapse as the positive charges on the rod neutralize the negative charges on the electroscope.

Question 28
A
3.86 x 105
B
3.56 x 105
C
1.80 x 104
D
2.16 x 105
Explanation.
Energy generated = power X time = 60w x 1h = 60 x 60 x 60 ws = 216000j = 2.16 x 105J

Question 29
A
5.60 v
B
24.00 v
C
0.24 v
D
2.40 v
Explanation.
Number of tunes, n = 500
Area, A = 0.2m + 0.2m = 0.4m2
change of flux density A B
= 1.0 - 0.4 = 0.6T
Tune, t = 5 su
Induced emf, = (AB AN)/AT
(0.6 x 0. 04 x 500)/5
= 2.4v

Question 30
A
ultraviolet rays
B
alpha particules
C
x - rays
D
infrared rays
Explanation.
Canorous cells can be destroyed with a high penetrating radiation which is x - rays

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