Nsep

If the threshold of hearing is assumed to be the reference (0 dB), then the threshold of pain is taken to be 120 dB. Let the corresponding sound intensities be I₀ and I respectively. Then I₀/I is

(a) 120 (b) 10¹² (c) 10^-12 (d) 10^1.2 

Which one of the following devices does not respond to the intensity of light incident on it ?

(A)  Photoresistor (LDR)

(B)  Photodiode

(C)  Light Emitting Diode

(D)   Solar Cell

A convex lens and concave lens are kept in contact and the combination is used for the formation of image of a body by keeping it at different places on the principal axis. The image formed by this combination of lenses can be : 

(A) Magnified, inverted and real

(B)  Diminished, inverted and real

(C) Diminished, erect and virtual

(D) Magnified, erect and virtual 

The frequency of the pendulum having maximum amplitude is 

(a)  f₀ / 2 

(b)  f₀ 

(c)   2 f₀ 

(d)  not related to  f₀

An isolated metallic object is charged in vacuum to a potential V₀ using a suitable source, its electrostatic energy being W₀. It is then disconnected from the source and immersed in a large volume of dielectric with dielectric constant K. The electrostatic energy of the sphere in the dielectric is :

(A)  K²W₀

(B)   K W₀

(C)   W_0/K²

(D)  W₀/K

The variation of amplitude A with respect to time t is shown as

Let a body be placed at a point on the earth’s surface at a latitude λ where the radius of the earth is R. Then, the body experiences an effective acceleration

(a)  g – Rω² cos λ

(b)  g + Rω² sin λ

(c)  g – Rω² cos² λ

(d)  g – Rω²/ cos²λ

In and atom an electron excites to the fourth orbit. When it jumps back to the energy levels a spectrum is formed. Total number of spectral lines in this spectrum would be 

(A)   3

(B)   4

(C)   5

 (D)   6 

Which one of the following statements is not a tautology ?

(1)  P → (p ∨ q)

(2)   (p ∧ q) → (~p) ∨ q

(3)  (p  ∧ q) → p 

(4)   (p ∨ q) → (p) ∨ (~q) 

A vertical narrow wire is illuminated with laser. Alternate dark and bright bands are formed on a graph paper pasted on a distant wall. Indicate the correct statement/s. 

(a)  making appropriate measurements, it is possible to determine the diameter of the wire 

(b)  this phenomenon exhibits that light does not follow rectilinear paths 

(c)  this is a case of Fraunhoffer diffraction 

(d)  this is a case of interference of an infinitely large number of Huygens’s secondary waves leading to a diffraction pattern