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| From: rishav_cool22 | Reply 221 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 54 |
It will nt change,,,,,,,
as radioactivity depends on neutrons and protons
whereas in a chemical change only electrons are invilved
therefore radioactivity will not be affected
Posted at: Fri Nov 26 15:27:53 2010 (GMT)
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| From: rishav_cool22 | Reply 222 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 57 |
sun.....
Posted at: Fri Nov 26 15:28:43 2010 (GMT)
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| From: vardarohilla | Reply 223 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 43 |
3
1/6+1/6=2/6
therefore Rp =6/2 =3 Ω
Posted at: Thu Dec 9 14:32:43 2010 (GMT)
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| From: meher7 | Reply 224 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 21 |
the amount of work done by a metal in unit time
Posted at: Fri Dec 10 06:14:37 2010 (GMT)
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| From: meher7 | Reply 225 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 34 |
the sound which reappears at regular intervals of time after the original
sound ceases is called echo. the distance between the source of sound and
echo should 17m,the intensity of sound should be suffecient
Posted at: Fri Dec 10 06:19:37 2010 (GMT)
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| From: meher7 | Reply 226 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 35 |
echo is used to find the depth of the sea,
Posted at: Fri Dec 10 06:22:42 2010 (GMT)
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| From: harshaktg | Reply 227 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 1 |
kg m/s
momentum = mass * velocity
p = m * v
As mass's SI unit is kg, and velocity's SI unit is m/s:
P's SI unit is:
p = (kg) * (m/s)
Therefore momentum's SI unit is kg m/s (or) kg m s-1
Posted at: Tue Dec 14 02:38:33 2010 (GMT)
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| From: harshaktg | Reply 228 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 2 |
Newton (or) kg m s -2
p = m * v
time is added, for rate of change of momentum
mass is constant
p/t = m * v/t
p/t is also known as FORCE.
v/t is also known as ACCELERATION
F = m * a
As we know, force's SI unit is Newton. We can say that the SI unit of rate
of change of momentum is also Newton
(or)
F = m * a
The SI unit of mass is kg.
The SI unit of acceleration is m/s2
F = (kg) * (m/s2)
Therefore we can also say that the SI unit of rate of change of momentum
is kg m/s2
Posted at: Tue Dec 14 02:44:41 2010 (GMT)
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| From: harshaktg | Reply 229 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 4 |
The answer is given below in the explanation
When the arrow is stretched, then is has Elastic potential energy. But,
after th arrow is released from the bow, that time the Potential energy is
converted to Kinetic energy
Posted at: Tue Dec 14 02:50:19 2010 (GMT)
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| From: harshaktg | Reply 230 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 5 |
The answer is given below in the explanation
(i) - Electric toaster = Electrical energy to Heat energy
(ii) - Microphone = Sound energy to Electrical energy
Posted at: Tue Dec 14 02:52:28 2010 (GMT)
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| From: harshaktg | Reply 231 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 6 |
The answer is clearly given below in the explanation
Load - the object on the palm of the hand is the load
Fulcrum - the elbow(joint) of the hand is the fulcrum
Effort - the forearm(muscle) or the part between the load and the fulcrum
is the effort
Posted at: Tue Dec 14 03:02:46 2010 (GMT)
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| From: harshaktg | Reply 232 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 9 |
It is due to friction
Due to friction the temperature of the water at the bottom will be different
from the temperature of the water at the top
Posted at: Tue Dec 14 03:04:56 2010 (GMT)
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| From: harshaktg | Reply 233 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 21 |
The answer is clearly given below in the explanation
Work fuction is the minimum amount of heat energy required to emit thermions
from the metal surface.
Posted at: Tue Dec 14 03:06:32 2010 (GMT)
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| From: harshaktg | Reply 234 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 3 |
14.7 N or 14.7 kg m s-2
We know that:
F = m * a (or g)
Therefore by substituting the values in this formula:
F = 1.50 * 9.80
F = 14.7 N (or) 14.7 kg m s-2
Posted at: Wed Dec 22 09:09:21 2010 (GMT)
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| From: harshaktg | Reply 235 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 7 |
The answer is clearly given below in the explanation
Speed of
light in air
Refractive index = -------------------------
Speed of light in glass
Posted at: Wed Dec 22 09:12:39 2010 (GMT)
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| From: harshaktg | Reply 236 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 8 |
The wavelength decreases
The wavelength decreases because the light moves from rarer medium to denser
medium.
Posted at: Wed Dec 22 09:14:13 2010 (GMT)
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| From: harshaktg | Reply 237 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 10 |
0.00015 sec
Distance = 45km = 45 * 1000 = 45000 m
Speed = 3*108 m/s
We know that:
D = S * T
T = D/S
By substituting the values in the above formula:
T = 45000/3*108
T = 0.00015 sec
Posted at: Wed Dec 22 09:26:21 2010 (GMT)
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| From: harshaktg | Reply 238 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 12 |
The answer is clearly given below
Primary colours are the colours which produce while light if they are mixed
in equal quantities. Those primary colours are red, green and blue.
Posted at: Wed Dec 22 09:30:14 2010 (GMT)
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| From: harshaktg | Reply 239 of 310 | Reply | |
| Subject: Contributed Answer/Explanation to Q. 14 |
resistance
Posted at: Wed Dec 22 09:33:31 2010 (GMT)
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| From: harshaktg | Reply 240 of 310 | Reply | View replies (1)
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| Subject: Contributed Answer/Explanation to Q. 16 |
The answer is clearly given below in the explanation
Posted at: Wed Dec 22 09:34:21 2010 (GMT)
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