A person can see the objects lying between 25 cm and 10 m from his eye. His vision can be corrected by using lens of power:
His distance of distinct vision at 25 cm is normal. By using a concave lens of focal length 10 m... View Article
Latest Posts
A slide projector gives a magnification of 10. If a slide of dimensions 3 cm x 2 cm is projected on the screen, the area of the image on the screen is:
Magnification=area of image / area of object Area of image = Magnification × area of object =10 (3 cm × 2 cm)... View Article
The potential barrier in the depletion region layer is due to :
The potential barrier in the depletion region layer is due to ions.
To use a transistor as an amplifier:
To use a transistor as an amplifier the emitter-base junction is forward biased and collector-base junction is reversed biased.
In an npn transistor, the collector current is 24 mA. If 80% of electrons reach collector, its base current in mA is
We know that, Ie = Ic + Ib Given 80% of Ie = Ic = 24 mA (80/100) Ie =24mA Ie= (24×100)/80... View Article
Which of the following is correct? Here, m represents the magnification of a mirror.
The m is +ve when image is formed by convex mirror.
For functioning of a transistor its emitter-base junction has to be:
For functioning of a transistor its emitter-base junction has to be forward biased.
An n p n transistor is biased to work as an amplifier. Which of the following statements is not correct?
If an n-p-n transistor is biased to work as an amplifier,the electrons go from the emitter region to the base... View Article
In case of a transistor, the central portion has to be :
In case of a transistor, the central portion may be N-type or P-type.
The phase difference between the input and output voltage of CE amplifier circuit is
The phase difference of 1800 between the signal voltage and output voltage in a common emitter amplifier is known as... View Article
Which of the following is the universal gate? (a) OR (b) NOT (c) AND (d) NAND
Option (d) NAND is the correct answer NAND gate and NOR gate are called the universal logic gates. The repeated use... View Article
Logic gate is a digital circuit with
Since Logic gate is a digital switching circuit, its output can have only one of the possible states i.e. either... View Article
According to Faraday’s law of electromagnetic induction
According to Faraday’s law of electromagnetic induction, the magnitude of induced e.m.f. produced in a coil is directly proportional to the... View Article
What is the focal length of a plane mirror?
The focal length of the plane mirror is infinite. The reason why a plane mirror has an infinite focal length... View Article
For seeing the cricket match we prefer binocular over terrestrial telescope. Why?
Binocular is preferred for observing a cricket match and not a terrestrial telescope because binocular gives a proper three-dimensional view.... View Article
The nature of the base of the transistor must be:
The nature of the base of the transistor must be opposite to that of collector and emitter.
The emitter of the transistor should be of:
The emitter is heavily doped, and its job is to emit and inject electrons for NPN (or holes for PNP)... View Article
In an n-p-n transistor, the majority carriers in the emitter and collector are :
The majority carriers in the emitter and collector are free electrons in an n-p-n transistor
An image is upright and reduced in size. Which mirror is used to form such an image?
Only Convex Mirror can form an image which is upright and reduced in size.
The base of the transistor should be:
The base of the transistor should be narrow so that most of the charge carriers can easily diffuse through it.
