Physics - Online Test

Q1. The Wheatstone bridge is balanced for four resistors R1,R2,R3 and R4 with a cell of emf 1.46 V. The cell is now replaced by another cell of emf 1.08 V. To obtain the balance again
Answer : Option D
Explaination / Solution:

The balance point of the Wheatstone’s bridge is determined by the ratio of the resistances. The change in the e m f of the external battery will have no effect on the balance point.

Q2. The damped natural frequency of a Damped system is
Answer : Option A
Explaination / Solution:

The damped natural frequency fis related to the natural frequency fn by a  relation 

 

where damping ratio   is <= 1 

so the fd is less than the natural frequency 


Q3. Referring to the Young’s double slit experiment, if D and d are distance from slit to screen and screen center to point P fringe width is given by
Answer : Option D
Explaination / Solution:
No Explaination.


Q4. For diamagnetic materials
Answer : Option B
Explaination / Solution:
No Explaination.


Q5. The total energy of a circularly orbiting satellite is
Answer : Option D
Explaination / Solution:

When a satellite revolves around a planet in its orbit, it possesses both potential energy (due to its position against the gravitational pull of earth) and kinetic energy (due to orbital motion).


Hence we can say that total energy of circularly orbiting satellite is negative.


Q6. Which of the following is not a semiconductor?
Answer : Option D
Explaination / Solution:

Materials that have the resistance levels between those of a conductor and an insulator are referred to as semiconductors. They are quite common, found in almost all electronic devices. Good examples of semiconductor materials are germanium, selenium, and silicon. Radium is a chemical element with symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals.

Q7. Instantaneous acceleration is defined as
Answer : Option B
Explaination / Solution:

instantaneous acceleration is measured over a "short" time interval. The word short in this context means infinitely small or infinitesimal — having no duration or extent whatsoever.

It's a mathematical ideal that can can only be realized as a limit. The limit of a rate as the denominator approaches zero is called a derivative.

Instantaneous acceleration is then the limit of average acceleration as the time interval approaches zero — or alternatively, acceleration is the derivative of velocity.


Q8. Speed of Sound is given by  where
Answer : Option B
Explaination / Solution:
No Explaination.


Q9. Infrared waves are sometimes referred to as heat waves because
Answer : Option D
Explaination / Solution:
No Explaination.


Q10. There are two stationary coils near each other. If current in coil-1 is changing with time, relationship of current in coil-2 to it's emf is described by
Answer : Option D
Explaination / Solution:


M is mutual inductance