Physics - Online Test
Q1. The propagation of light is best described by,
Answer : Option D
Explaination / Solution:
No Explaination.
Q2. Which of the following statements about bar magnets is correct ?
Answer : Option D
Explaination / Solution:
As magnetic monopole does not exist. If we split the bar magnet into two pieces each part will have its own north and south pole.
Q3. According to Kepler’s Law of areas,
Answer : Option A
Explaination / Solution:
Kepler law of areas describes the speed of a planet travelling in an elliptical orbit around the sun. A planet’s orbital speed changes, depending on how far it is from the Sun. The closer a planet is to the Sun, the stronger the Sun’s gravitational pull on it, and the faster the planet moves. The farther it is from the Sun, the weaker the Sun’s gravitational pull, and the slower it moves in its orbit. So, statement of Kepler's law of area is "The line joining the sun to the planet sweeps out equal areas in equal interval of time". i.e. areal velocity is constant.
Q4. In the case of metals the valence and conduction bands have
Answer : Option C
Explaination / Solution:
The materials can be classified by the energy gap between their valence band and the conduction band. The valence band is the band consisting of the valence electron, and the conduction band remains empty. Conduction takes place when an electron jumps from valence band to conduction band and the gap between these two bands is forbidden energy gap. Wider the gap between the valence and conduction bands, higher the energy it requires for shifting an electron from valence band to the conduction band.
- In the case of conductors, this energy gap is absent or in other words conduction band, and valence band overlaps each other. Thus, electron requires minimum energy to jump from valence band. The typical examples of conductors are Silver, Copper, and Aluminium.
- In insulators, this gap is vast. Therefore, it requires a significant amount of energy to shift an electron from valence to conduction band. Thus, insulators are poor conductors of electricity. Mica and Ceramic are the well-known examples of insulation material.
- Semiconductors, on the other hand, have an energy gap which is in between that of conductors and insulators. This gap is typically more or less 1 eV, and thus, one electron requires energy more than conductors but less than insulators for shifting valence band to conduction band.
Q5. for motion in a straight line
Answer : Option A
Explaination / Solution:
To describe motion along a straight line, we can choose an axis, say X-axis, so that it coincides with the path of the object. We then measure the position of the object with reference to a conveniently chosen origin, say O, Positions to the right of O are taken as positive and to the left of O, as negative.
Q6. Maxwell’s displacement current is a response to
Answer : Option C
Explaination / Solution:
No Explaination.
Q7. When we make a mobile telephone call to a friend
Answer : Option D
Explaination / Solution:
Because mobile communication is a space communication and in space communication basically electromagnetic waves are used (as carrier waves as in case of radio communication) because of the modulation ( frequency, amplitude) operations which can be performed on EM waves. Thus when our friend receives the call, he also receives EM waves which is the carrier of our audio signals.
Q8. In pure translational motion of a rigid body
Answer : Option C
Explaination / Solution:
In translational motion when the body moves along a straight line or more exactly when every point of the body travels on paralell lines, thus at any instant of time every particle of the body has the same velocity.
Q9. When a bar magnet is pushed towards the coil connected in series with a galvanometer, the pointer in the galvanometer G
Answer : Option B
Explaination / Solution:
When bar is in motion then flux will changed hence current will be induced.
Q10. In which case is electron emission from a metal not known?
Answer : Option A
Explaination / Solution:
No Explaination.
