Physics - Online Test
Q1. Polarity of the capacitor in the situation described by the adjacent figure is
Answer : Option C
Explaination / Solution:
A will become positive with respect to B because current indused is in clockwise direction
Q2. If h is Planck’s constant, the momentum of a photon of wavelength 0.01 is
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. A body of mass m is taken from earth surface to the height h equal to radius of earth, the increase in potential energy will be
Answer : Option B
Explaination / Solution:
Work done=mgh1+hRIf h=R then,⇒Work done=mgh1+RR=12mgh
Q4. Repeater is used for
Answer : Option B
Explaination / Solution:
In telecommunications, a repeater is an electronic device that receives a signal and retransmits it.Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction.
Q5. A cyclist starts from the centre O of a circular park of radius 1 km, reaches the edge P of the park, then cycles along the circumference anticlockwise from P to Q, and returns to the centre along QO as shown in Figure. If the round trip takes 10 min, what is the (a) net displacement, (b) average velocity, and (c) average speed of the cyclist ?
Answer : Option D
Explaination / Solution:
(a) displacement is shortest distance b/w initial point and final point, as he returns back to origin after starting from origin, the displacement is zero.
(b) Average velocity =
As displacement is zero, so average velocity is also eqaul to zero.
(c) Radius r = 1 km
distance covered = OP+PQ+QO
=
= km
Time taken = 10 minutes = hour
Average speed
21.4 km/h
Q6. A conducting sphere of radius 5 cm is charged to 15 μ C. Another uncharged sphere of radius 10 cm is allowed to touch it for enough time. After the two are separated, the surface density of charge on the two spheres will be in the ratio
Answer : Option A
Explaination / Solution:
Q7. Material is said to be brittle if
Answer : Option A
Explaination / Solution:
No Explaination.
Q8. The Carnot cycle consists of
Answer : Option C
Explaination / Solution:
The Carnot cycle consists of the following four processes:
- A reversible isothermal gas expansion process
- A reversible adiabatic gas expansion process
- A reversible isothermal gas compression process
- A reversible adiabatic gas compression process
Q9. In which of the following cases is the work done positive?
Answer : Option C
Explaination / Solution:
Work done is positive when force applied and displacement are in same direction.
in this case angle between force and displacement is zero (i.e. ) so that work done is positive.
Q10. In a Geiger -Marsden experiment, what is the distance of closest approach d to the nucleus of a 7.7 MeV α−particle before it comes momentarily to rest and reverses its direction?
Answer : Option C
Explaination / Solution:
No Explaination.
