Physics viva

Question 1

Gate

Answer 1

A digital circuit that maintains a logical link between the input and the output voltages (either let/prohibit signal from passing)

Question 2

Logic gate

Answer 2

Employed to convert one voltage level to another acc to a logic statement pertaining.
2. Only has one output although may have more than one input.

Question 3

Truth table

Answer 3

Table which expresses the relationship between possible values of input and output voltages

Question 4

Boolean algebra

Answer 4

Algebra based on binary nature of logic gates

Question 5

Principle of project

Answer 5

Any boolean algebraic operation can be associated with the input and output which represents the statement of Boolean algebra

Question 6

Components

Answer 6

Despite the complexity of the circuits, they can all be built using three fundamental components: an NPN transistor, resistance and a PN junction diode

Question 7

Aim

Answer 7

To explore logic gates with their truth tables

Question 8

Objectives

Answer 8

Explain basic logic operations (clarify fundamental logic operations), demonstrate circuit building (demonstrate building and simulating logic circuits), create truths (teach how to construct truths for logic gates)

Question 9

Application

Answer 9

Computer science, electrical engineering, robotics, biology. Support modern computing and decision-making systems.

Question 10

Forward, reverse biasing and their applications

Answer 10

When p side of diode connected to positive terminal forward.

zener Diode are connected in reverse bias for voltage regulation. When a PN junction diode is used in a rectifier circuit, it needs forward biasing.

Question 11

Formula of finding resistance using metre bridge

Answer 11

X equals 100 minus L divided by L multiplied by R, Where L is the length of meter bridge wire, zero and up to balance point

For a balanced wheat stone bridge, R1 by R2 equals R3 by R4

Question 12

Circuit diagram of metre bridge

Question 13

Sources of error for finding resistance using meter bridge

Answer 13

the instruments screws may be loose

the plugs may not be clean.

The wire may not have uniform thickness

the screw gauge may have falls like backlash error and wrong pitch

Question 14

Precautions for resistance using meter bridge

Answer 14

The connections should be neat, clean and tight

All the plugs in the resistance box should be tight

Move the jockey gently over the bridge wire and do not rub it

The plug in the key should be inserted only when observations are to be taken

Question 15

Theory of finding the focal length of a convex mirror using a convex lens

Answer 15

F equals R/2

Because a convex mirror always forms a virtual image Its focal length cannot be found directly as for a concave mirror.

For this purpose, indirect method is used

Question 16

Ray diagram for finding focal length of a convex mirror using a convex lens

Question 17

Sources of error for optics

Answer 17

The uprights may not be vertical

Parallax removal may not be perfect

Focal length of lens may not be small

Question 18

Precautions for finding focal length of a convex mirror using a convex lens

Answer 18

Principal axis of the lens should be horizontal and parallel to the line of the optical bench

All the uprights should be vertical

The tip of the needle centre of the mirror and centre of the lens should be at the same height

Tip to tip parallel should be removed

Question 19

Theory of finding the focal length of a convex lens by plotting graphs between U and V

Answer 19

The relation between U, V and F for a convex lens is _ Lens formula_

Question 20

Ray diagram for finding the focal length of a convex lens by plotting graphs between U and V

Question 21

Precautions for finding focal length of a convex lens by plotting graphs between U and V

Answer 21

Tips of the object and image needle should lie at the same height at the centre of the lens

Parallax should be removed from tip to tip by keeping eye at a distance at least 30 cm away from the needle

The object needle should be placed at such a distance that only real, inverted image of it is formed

Index correction for U and V should be applied

Question 22

Theory for studying the variation in potential drop with length for a wire for a steady current

Answer 22

According to OMS law V equals IR also R equals ρl by A, put the above relations combined, give us V proportional to L

Question 23

Circuit diagram for studying the variation in potential drop with length for a wire for a steady current

Question 24

Common sources of error (activity)

Answer 24

Personal error (improper connection)
Resistance of wire
Instrumental error

Question 25

Precaution for correcting circuit

Answer 25

1. All the electrical connections must be neat and tight.
2. Switch On the power source when the circuit is connected properly.
3. Avoid contacting circuits with wet hands or wet materials.

Question 26

Theory of correcting circuit

Answer 26

Circuit functional only when components in proper order (working)

Open circuit is break in circuit
-could be deliberate
-fault in circuit (broken wire, burnt/loose connection

Question 27

Circuit diagram for correcting circuit

Question 28

Circuit diagram for studying variation in potential drop with length

Question 29

Observation for metre bridge experiment

Answer 29

Length of wire of unknown resistance

Least count, zero error, zero correction of screw gauge

Question 30

Observation table for metre bridge experiment

Answer 30

Unknown resistance

Resistance box, position of balance point,s
Mean resistance
Resistivity
Respective errors

Diameter of wire

Reading along mutually perpendicular directions: MSR, CSD, diameter
Mean diameter

Question 31

Observation for correcting circuit

Answer 31

Correct connection, incorrect connection

Question 32

Observation for potential difference with length of wire

Answer 32

Range, least count, zero error of voltmeter

Question 33

Observation table for potential difference with length of wire

Answer 33

Length of potential wire, volt meter reading, Φ

Question 34

Calculation for metre bridge experiment

Answer 34

Calculate Ρ using formula

Error:
Delta S:directly differentiate, Max of S1 and S2
Delta radius ,delta l: least counts of measuring instruments

Question 35

Calculation for potential difference wire

Answer 35

φ = V/L

Question 36

Result of meter bridge, experiment

Answer 36

S, Ρ

Question 37

Result of correcting circuit

Answer 37

The electrical circuit assembled as per the corrected circuit diagram is functional

Question 38

Result of potential difference using wire

Answer 38

φ is found to be constant. The graph shows a linear relationship.

Question 39

Precaution for potential difference using wire

Answer 39

Adjust zero error of voltmeter and ammeter by adjusting screw at base of needle

Don’t press the wire too hard with the jockey to avoid non-uniformity

Check for wire uniformity

Current should remain constant throughout the experiment: monitored by ammeter, readjusted with rheostat, current drawn intermittently for short duration of time

Question 40

Observation of finding focal length of convex mirror using convex lens

Answer 40

Focal length of the convex lens
Actual length of index needle
Observed length of index needle
Index correction equals actual minus observed