Physics - Online Test
Q1. All files are stored in the ______________
Answer : Option A
Explaination / Solution:
No Explaination.
Q2. A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is,
Answer : Option B
Explaination / Solution:
End
A of the rod acts as an object for mirror and A' will be its image. By mirror
formula, image distance of A is VA.
VA
= -15cm
Also
image distance of C
Vc= -20 cm
∴ The length of image = | VA-VC
|
= | -15-(20) | = 5cm
Q3. A sample of ideal gas is at equilibrium. Which of the following quantity is zero?
Answer : Option C
Explaination / Solution:
No Explaination.
Q4. 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.
Q5. Maxwell’s displacement current is a response to
Answer : Option C
Explaination / Solution:
No Explaination.
Q6. Two point white dots are 1 mm apart on a black paper. They are viewed by eye of pupil diameter 3 mm approximately. The maximum distance at which these dots can be resolved by the eye is, [take wavelength of light, λ = 500 nm]
Answer : Option B
Explaination / Solution:
Resolution
limit = 1.22 × λ / D
D
- diameter of pupil = 3 mm
λ
- wavelength = 500 nm
Resolution limit = distance between the dots / resolving diameter
=
1mm/d
[
1.22 × λ ] / D = 1mm / d
D
= [1mm × D ] / [ 1.22 × λ ] = [ 1
x 10-3 × 3 x 10-3 ] / [ 1.22 × 500 x10-9 ]
d = 4.918 ≈ 5m
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. A particle executing SHM crosses points A and B with the same velocity. Having taken 3 s in passing from A to B, it returns to B after another 3 s. The time period is
Answer : Option C
Explaination / Solution:
No Explaination.
Q9. Which charge configuration
produces a uniform electric field?
Answer : Option C
Explaination / Solution:
No Explaination.
Q10. In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Broglie wavelength associated with the electrons would
Answer : Option C
Explaination / Solution:
deBroglie
wavelength λ ∝ 1/√V
λ1/λ2 = √(V2/V1)
= √(224/14) = √16 = 4
λ1
= 4λ2
λ2
= λ1/4
