MHTCET 14 May 2023 Shift 1 Solved Paper

In a common emitter configuration, the parameters ' α ' (alpha) and ' β ' (beta) are related as follows:
α is the current gain in a common base configuration and β is the current gain in a common emitter configuration. The relationships between ' α ' and ' β ' are given by:
β=‌

α

1−α

and
α=‌

β

β+1

Let's examine the given options one by one to determine the incorrect relation:
Option A: ‌

1

α

=‌

1

β

+1
Rewriting this equation:
‌

1

α

=‌

1

β

+1
This can be written as:
‌

1

α

=‌

1+β

β

Therefore, this is a correct relation.
Option B:α=‌

β

1−β

We know that:
α=‌

β

β+1

Clearly, ‌

β

1−β

does not match this, so this is the incorrect relation.
Option C:α=‌

β

1+β

We know that:
α=‌

β

β+1

This is the correct relation.
Option D: ‌

1

β

=‌

1

α

−1
Rewriting this equation:
‌

1

β

=‌

1

α

−1
This can be written as:
‌

1

β

=‌

1−α

α

From the relation β=‌

α

1−α

, inverting both sides we get:
‌

1

β

=‌

1−α

α

Therefore, this is a correct relation.
In conclusion, the incorrect relation between ' α ' and ' β ' is Option B:α=‌

β

1−β

.