2007junep3

Magnitude of the force increases
When the speed increases, the centripetal force needed increases. If the
frictional force between the road and the tyre is not sufficient to provide this ,
the car will leave the track

Travels with uniform speed of 25cm/s
1
3 25 7 25 212.5
2
cm
    
25
/ / 8.33 / ... .. ..1
3
cm s s cm s in every s


Weight W creates an anticlockwise moment whereas the force of the steam creates a
clockwise moment. If the clockwise moment is greater than the anti clockwise
moment, the valve will open

12 0.2
12
60
0.2
F
F N
 
  60N
60
200,000
0.0003
F
P Pa
A
  

tan
60 10 3 1800
W Force dis ce
weight height
mgh J
 
 
    

.. 1800
150
12
work done
Power W
time
  
As she walks down, gravitational potential energy changes to kinetic energy and sound and
heat. This energy changes to heat energy as she stops at the bottom

Mass of beaker + stirrer + thermometer + water
Mass of beaker + stirrer + thermometer + water + ice
Heat lost= mass x sp. Heat capacity x temp. fall
Heat energy= mass of melted ice x sp latent heat of fusion of ice

12800
426.7 /
30
f
f
E mL
E
L J g
m

  
Heat energy from the surroundings also melts the ice.
Temp of the beaker decreases. Heat energy from the beaker also melts
the ice

Keep the two containers at equal distance from the bunsen flame and wait
for some time. Note the reading on both the thermometers.
Thermometer in the dull black container will show a greater reading
High sensitivity means the thermometer is capable of detecting very small
change in temperature.
Rise in temperature in this experiment is very less.so thermometer with high
sensitivity is needed
If the thermometer has linear scale , level of mercury will increase by equal
amount for an equal in crease in temperature

89 degrees
43 degrees
1 1
.. 1.47
sin. sin 43
refractive index
C
  
8
8
8
.. .. .. ..
..
.. .. .. ..
3.0 10
1.47
.. .. ..
3.0 10
.. .. 2.04 10 /
1.47
speed of light in vacuum
refracive index
speed of light in medium
speed of light medium
speed in medium m s




  

Stopwatch, measuring tape, two flat pieces of wood
Stand at a distance of about 100m and one boy makes sound using wooden
pieces. Measure the distance travelled by the sound and the time taken by the
sound to reach
tan .. .. ..
..
dis ce travelled by sound
speed
time taken


Repeat the experiment by exchanging their position so that the sound will travel in
the opposite direction

36
3
12
P
I A
V
  
3A
12
4
3
V
R
I
   
1 2
1 2
4 4
2
4 4
R R
R
R R

   
 
12 3 30 1080
E VIt J
    

As the lamps A and B are connected in series, battery voltage is divided
across them. The voltage across each lamp is 6V and so the power is less

As the switch is closed current from the wheel flows to the dish of mercury through
the conductor which is in the magnetic field .As the current flows perpendicular to
the magnetic field, a force acts on it

The split ring commutator reverses the direction of current in the coil after every
half turn and the motor will turn continuously in the same direction

Thermistor when heated, resistance across it decreases and so the pd across it
decreases. The pd across the R1 increases. As the pd between the emitter and the
collector increases, the lamp lights up.

The resistor R1 can be replaced by using a variable resistor so that the lamp can
be made to light up at a desired temperature. If the lamp is replaced by an air
conditioner, it can switch on automatically when temp increases
To switch on the AC when the temperature increases.

As the positively charged alpha particles get repelled away by the nucleus, the nucleus is
positive and as the number that bounces back is less, size of the nucleus is small

2007junep3

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