Draw and explain, Block diagram of Direct Sequence Spread Spectrum (DSSS)

 

I am not very good in maths and physics could I succeed in studying B-tech

* First of all, you have to think are you confident from inner-self ? to move ahead towards B-tech study.

* Are you interested to do this with patience, without taking any worry.

* It is not matter how much you weak in any subject, it is only matter about your choice of confidence in any stream.

* You have to not think like, I am not good in this subject. You have to think like, why I am wanting to go in B-tech study.

* What is main motive for me to doing B-tech.

* Think our-self, Can I only do this because of good package salary or just for high reputation.

* So my friends, its very simple to take decision about yourself.

just talk this worlds with yourself and think on it and then take any decision on it.

Application of elasticity | Physics

 1) while designed concrete or steel structure it is design to bear more load than actual load.

 2) To determine strength of material.

3) In engineering to determine tensile strength of different of different material.

4) The elasticity property has to be taken into account in the construction of building and fly over, bridges etc.

5) When we wind a watch its spring is strained and energy is stored in it as strained energy, the spring slowly rotates inside of the watch due to strain energy.

Defination of stress | Physics

* Ultimate stress: It is the maximum stress with which system is                                          capable of withstanding.

* Working stress: It is the actual load on the system.

* Breaking stress: It is the maximum stress at which wire will breaks.

* Factor of safety: It is the ratio of ultimate stress to working stress.

Difference between elastic body and Plastic body | Physics

                      Elastic body 

Definition: The property on account of which a body regain it's original size and shape on removal of external deforming force is called as elastic body.

Process:  It is reversible.

Ductility: It is less ductile in nature.

Modulus of elasticity: The ratio of stress to strain is low or equal.

Toughness: They have the ability to absorb energy up to fracture.

Bonds: The molecular bonds do not get fractured.

Shape and size: The shape and size does not change permanently.

Example: Rubber.

                               Plastic body

Plastic body: The property on account of which a body doesn't regain its original size and shape on removal of applied force is called as plastic body.

Process: it is irreversible

Ductility: They are highly ductile in nature.

Resilience: They have low yield strength.

Modulus of elasticity: The ratio of stress to strain is high.

Toughness: They do not have the ability to absorb energy up to a fracture.

Bonds: The molecular bonds are fractured.

Shape and size: The shape and size changes permanently.

Example: Plasticine

              

Explain Viva of Electrostatics | physics

1) What is electrostatics ?

Ans: It is the branch of science which deals with the study of electric charges and force between them.

2) Definition of electric charge 

Ans: It is the physical property of the matter that experience a force when it is place in electric field there are two types of electric charge. 

 i) Positive    charge (+ve)

 ii) Negative  charge  (-ve)

It is denoted by q and it's unit is coulomb (c)

3) Explain coulomb low of electrostatics or coulomb Inverse square low 

Statement: It states that the force of attraction or repulsion between two electric charges is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them.

4) Definition of electric field.

Ans: The space around the electric charge is called as electric field.

5) Definition of electric flux density.

Ans: The total number of electric lines of force per unit Area is called as electric flux density. and it is denoted by (D).

6) Definition of Electric field intensity.

Ans: The force Acting Per unit charge is called as electric field intensity. It is denoted by (E).

7) Definition of Electric flux.

Ans: The total number of electric lines of force is called as electric flux. And it is denoted by ψ (Psi) it unit is coulomb.

8) Definition of electric potential.

Ans: The amount of work done in bringing a unit positive charge from the boundary of infinity to a given point against electric field is called as electric potential and it is denoted by (v).

9) Definition of absolute potential (v).

Ans: The amount of work done is bringing a unit positive charge at a given point is called as absolute potential.

10) Definition of electric potential between two points.

Ans: The amount of work done is bringing a unit positive from point R to points S is called as potential difference between two points.

List requirements of good servo motors.

 i) The linear relationship in between electrical control signal and the rotor speed over a wide range.

ii) The inertia of rotor should be as low as possible.

iii) A servo motor must stop running without any time delay, if control signal is removed.

iv) For low inertia, it is designed with large length to diameter ratio for rotors, compared to its frame size. The rotor of servomotor has very small diameter.

v) It's response should be as fast as possible, for quickly changing error signal, it must react with good response. This is attain by keeping torque to weight ratio high.

vi) It should be easily reversible. 

vii) It should have linear torque speed channel.

viii)  It's operation should be stable without any oscillation or overshoot.

State disadvantage of single mode optical fiber

 Ans:-

i) The laser required are costly and can be used with only one cable at a time.

ii) The dependency on laser it means that single mode cables are less versatile and more limited in their applications.

iii) Single mode solution are often more expensive to deploy and operate since laser based equipment generate more heat.

State advantage of WDM

 Ans:-

i) To use the full capacity of the fiber optic cable by allowing multiple beams of light at different frequencies on the same fiber    optic cable.

ii) Full duplex transmission is possible.

iii) Easier to reconfigure.

iv) Optical components are similar and more reliable.

v) This could be the best approach, as it is simple to implement.

vi) High security.

vii) Various optical channel can support different transmission formats.