Physics viva Flashcards
Gate
A digital circuit that maintains a logical link between the input and the output voltages (either let/prohibit signal from passing)
Logic gate
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.
Truth table
Table which expresses the relationship between possible values of input and output voltages
Boolean algebra
Algebra based on binary nature of logic gates
Principle of project
Any boolean algebraic operation can be associated with the input and output which represents the statement of Boolean algebra
Components
Despite the complexity of the circuits, they can all be built using three fundamental components: an NPN transistor, resistance and a PN junction diode
Aim
To explore logic gates with their truth tables
Objectives
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)
Application
Computer science, electrical engineering, robotics, biology. Support modern computing and decision-making systems.
Forward, reverse biasing and their applications
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.
Formula of finding resistance using metre bridge
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
Circuit diagram of metre bridge
Sources of error for finding resistance using meter bridge
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
Precautions for resistance using meter bridge
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
Theory of finding the focal length of a convex mirror using a convex lens
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
Ray diagram for finding focal length of a convex mirror using a convex lens
Sources of error for optics
The uprights may not be vertical
Parallax removal may not be perfect
Focal length of lens may not be small
Precautions for finding focal length of a convex mirror using a convex lens
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
Theory of finding the focal length of a convex lens by plotting graphs between U and V
The relation between U, V and F for a convex lens is _ Lens formula_
Ray diagram for finding the focal length of a convex lens by plotting graphs between U and V
Precautions for finding focal length of a convex lens by plotting graphs between U and V
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
Theory for studying the variation in potential drop with length for a wire for a steady current
According to OMS law V equals IR also R equals ρl by A, put the above relations combined, give us V proportional to L
Circuit diagram for studying the variation in potential drop with length for a wire for a steady current
Common sources of error (activity)
Personal error (improper connection)
Resistance of wire
Instrumental error
Precaution for correcting circuit
- All the electrical connections must be neat and tight.
- Switch On the power source when the circuit is connected properly.
- Avoid contacting circuits with wet hands or wet materials.
Theory of correcting circuit
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
Circuit diagram for correcting circuit
Circuit diagram for studying variation in potential drop with length
Observation for metre bridge experiment
Length of wire of unknown resistance
Least count, zero error, zero correction of screw gauge
Observation table for metre bridge experiment
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
Observation for correcting circuit
Correct connection, incorrect connection
Observation for potential difference with length of wire
Range, least count, zero error of voltmeter
Observation table for potential difference with length of wire
Length of potential wire, volt meter reading, Φ
Calculation for metre bridge experiment
Calculate Ρ using formula
Error:
Delta S:directly differentiate, Max of S1 and S2
Delta radius ,delta l: least counts of measuring instruments
Calculation for potential difference wire
φ = V/L
Result of meter bridge, experiment
S, Ρ
Result of correcting circuit
The electrical circuit assembled as per the corrected circuit diagram is functional
Result of potential difference using wire
φ is found to be constant. The graph shows a linear relationship.
Precaution for potential difference using wire
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
Observation of finding focal length of convex mirror using convex lens
Focal length of the convex lens
Actual length of index needle
Observed length of index needle
Index correction equals actual minus observed
