ALL PHYSICS DOUBTS - POST HERE !!

[haris94]

one question - applies to the same diagram above
if the d.c output is from a bridge rectifier, the negative current is converted to positive and the output on the screen will be like diagram 2.
am i right?

[Saladin]

yes, that is true.

[holtadit]

one question - applies to the same diagram above
if the d.c output is from a bridge rectifier, the negative current is converted to positive and the output on the screen will be like diagram 2.
am i right?

So your saying if a diode receives an AC input the output will be the second diagram ?

[Saladin]

a diode has nothing to do with this.

a diode, simply has the ability to block current, and block 100% of it.

so say u giv an alternating current.

the di-ode will block everything.

which is unlike a recitifier, which will ony block a the alternating current.

[haris94]

normally if an a.c supply is given, the diode used (1 diode) allows current to flow only in one direction
this means it will allow the positive current to flow and will block the negative
(an ac supply has both positive and negative current)
since the negative part is blocked, the output will be the the positive bump and the negative which is a straight line (like your first diagram)

a bridge rectifier is different. here u use 4 diodes and the negative current is converted (not blocked) to positive current
and so the output curve will be the positive bumps repeated continuously (like your second diagram)

got it ?

[The Golden Girl =D]

Okay never mind that.


Heres my next query. For a D.C. output how should I draw the waves ? The first picture (top) or second one (bottom) ?

i am srry to say that guys u r wrong ..the right one is the second one ....but as for the first one it's when a diode is used "which changes ac to dc " 

[nid404]

the golden girl is right...it's the 2nd diagram....i dunno how i missed this 1...

[holtadit]

How is the answer c

[Amr Fouad]

How is the answer c

Thermal capacity depends on 2 things:

1. mass of object
2. Type of material

we will not use number 2 as all are made of copper..however, we will use point 1..

a tube is hollow, while a rod is not, therefore a rod is heavier, ie greater mass..

therefore, the answer should be A or C..and since C is heavier,

C is the correct answer..

got that Ari?

[Amr Fouad]

plus the question asks "which ROD.."

lol..so it shud be A or C 

[holtadit]

Thanks again...

[Amr Fouad]

Thanks again...

anytime 

[~HyDrOgEn~]

what is meant by terminal velocity? thanks!

[Saladin]

The velocity at which there is no resultant force. The body is in constant motion.

[hmh]

what is meant by terminal velocity? thanks!

The velocity when a falling object is no longer accerlerating; the force due to gravity is equal to the opposing force of air resistance.