Questions:
ARE ALL UR MOTHER IS RENDI HIZRA. AND ALL OTHERX LIKE CUSTOM
Answers
Construction and Working:
This principle can be demonstrated and explained through Faraday's experiments.
A transformer consists of primary and secondary coils insulated from each other, wound on a soft iron core (figure). To minimise eddy current a laminated iron core is used. The a.c. input is applied across the primary coil. The continuously varying current in the primary coil produces a varying magnetic flux in the primary coil, which in turn produces a varying magnetic flux in the secondary. Hence, an induced emf is produced across the secondary.
Let E
P
and E
S
be the induced emf in the primary and secondary coils and N
P
and N
S
be the number of turns in the primary and secondary coils respectively. Since same flux links with the primary and secondary, the emf induced per turn of the two coils must be the same
i.e.,
N
P
E
P
=
N
S
E
S
(or)
E
P
E
P
=
N
P
N
S
....(1)
For an ideal transformer, input power = output power
E
P
I
P
=E
S
I
S
where I
P
and I
S
are currents in the primary and secondary coils.
i.e.,
N
P
E
S
=
I
S
I
P
....(2)
From equations (1) and (2)
E
P
E
S
=
N
P
N
S
=
I
S
I
P
=k
Where k is called transformer ratio.
(for step up transformer k>1 and for step down transformer k<1)
In a step up transformer E
S
>E
P
implying that I
S
<I
P
. Thus a step up transformer increases the voltage by decreasing the current, which is in accordance with the law of conservation of energy. Similarly a step down transformer decreases the voltage by increasing the current.
Efficiency of transformer is defined as the ratio of output power to the input power.
η=
Inputpower
Outputpower
=
E
P
I
P
E
S
I
S
The energy losses of a transformer are (i) Copper less, (ii) Hysteresis loss, (iii) Eddy current loss, (iv) Flux loss.
Answer:
A compound microscope is an upright microscope that uses two sets of lenses (a compound lens system) to obtain higher magnification than a stereo microscope. A compound microscope provides a two-dimensional image, while a stereo microscope provides a three-dimensional image.
Explanation:
#Hope you have satisfied with this answer.
