GK in English

GK Chapterwise – CDS Previous Year Papers

Table of Contents

121. The rate of change of momentum of a body equal of the resultant:

(a)energy
(b) power
(c) force
(d) impulse
Ans: (c)

CDS (II) 2008

122. A person rings a metallic bell near a strong concrete wall.
He hears the echo after 0.3 s. if the sound moves with a speed of 340 m/s, how far is the wall from him?

(a)102 m
(b) 11 m
(c) 51 m
(d) 30 m
Ans: (c)
CDS Exam (II) 2010

123. Liquids and gases never show

(a)diamagnetic property
(b) paramagnetic property
(c) ferromagnetic property
(d) electromagnetic property
Ans: (c)
CDS Exam (I) 2015

124. The energy of a photon, whose momentum is 10 MeV/ c, where c is the speed of light, is given by

(a)10 MeV
(b) 100 MeV
(c) 1 MeV
(d) 0.1 MeV
Ans: (a)

CDS (I) 2011

125. In total internal reflection, the light travels from

(a)rarer to denser medium and it occurs with no loss of intensity
(b) denser to rarer medium and it occurs with no loss of intensity
(c) rarer to denser medium and it occurs with loss of intensity
(d) denser to rarer medium and it occurs with loss of intensity
Ans: (b)

CDS (II) 2013

126. Which one of the following physical quantities has the same dimensions as that of Planck’s constant h?

(a)Linear momentum
(b) Angular momentum
(c) Force
(d) Potential energy
Ans: (b)
CDS Exam (II) 2017

127. The pressure exerted by a 760 mm column of mercury at 0°C is known as

(a)1 pascal
(b) 1 atmosphere
(c) 1 bar
(d) 1 poise
Ans: (b)

CDS (II) 2015

128. A parallel-plate capacitor, with air in between the plates, has capacitance C. Now the space between the two plates of the capacitor is filled with a dielectric of dielectric constant
7. Then the value of the capacitance will become

(a)C
(b) C 7
(c) 7C
(d) 14C
Ans: (c)

CDS (I) 2019

129. Which one of the following is not a semiconductor?

(a)Silicon
(b) Germanium
(c) Quartz
(d) Gallium arsenide
Ans: (c)

CDS (II) 2012

130. Suppose voltage V is applied across a resistance R, The power dissipated in the resistance is P. Now the same voltage V is applied across a parallel combination of three equal resistors each of resistance R. Then the power dissipated in the second case will be

(a)P
(b) 3P (c) P/3
(d) 2P/3
Ans: (b)
CDS Exam (II) 2007

131. When a piece of pure silicon is doped with aluminium, then

(a)the conductivity of the doped silicon piece will remain the same
(b) the doped silicon piece will become n-type
(c) the doped silicon piece will become p~type
(d) the resistivity of the doped silicon piece will increase
Ans: (c)

CDS (II) 2009

132. Light travels in a straight line (rectilinear propagation of light). This statement does hold if the medium of travel for light is

(a)of variable refractive index
(b) made up of slabs of different refractive indices
(c) homogeneous and transparent
(d) inhomogeneous and transparent
Ans: (c)

CDS (I) 2018

133. A photon of X-ray has energy of 1 keV. A photon of visible radiation has energy of 3 eV. In this context, which one of the following statements is not correct?

(a)The wavelength of X-ray photon is less than the wavelength of visible radiation photon.
(b) Both the photons have different energies.
(c) The speeds of both the photons in vacuum are different.
(d) The frequency of X-ray photon is higher than the frequency of visible radiation photon.
Ans: (c)

CDS (II) 2016

134. A parallel-plate capacitor of capacitance C1 is made using two gold plates. Another parallel-plate capacitor of capacitance C2 is made using two aluminium plates with same plate separation, and all the four plates are of same area. If rg and ra are respectively the electrical resistivities of gold and aluminium, then which one of the following relations is correct?

(a)C1 > C2
(b) C2 > C1
(c) C1Cra = C2Crg
(d) C1 = C2
Ans: (d)
CDS Exam (II) 2008

135. A copper wire of radius r and length l has a resistance of R.
A second copper wire with radius 2r and length l is taken and the two wires are joined in a parallel combination. The resultant resistance of the parallel combination of the two wires will be

(a)5R
(b) 5 R 4
(c) 4 R 5
(d) R 5
Ans: (d)

CDS (II) 2010

136. Consider the electromagnetic radiations having wavelengths 200 nm, 500nm and 1000 nm. Which wavelength(s) of the following can make visual sensation to a human eye?

(a)200 nm and 500 nm
(b) 500 nm and 1000 nm
(c) 500 nm only
(d) 200 nm and 1000 nm
Ans: (c)

CDS (I) 2015

137. For which one of the following does the centre of mass lie outside the body?

(a)A fountain pen
(b) A cricket ball
(c) A ring
(d) A book
Ans: (c)
CDS Exam (I) 2011

138. Infrared, visible and ultraviolet radiations/light have different properties. Which one of the following statements related to these radiations/light is not correct?

(a)The wavelength of infrared is more than that of ultraviolet radiation.
(b) The wavelength of ultraviolet is smaller than that of visible light.
(c) The photon energy of visible light is more than that of infrared light.
(d) The photon energy of ultraviolet is lesser than that of visible light.
Ans: (d)
CDS Exam (II) 2013

139. A ray of light is incident on a plane mirror at an angle of 40° with respect to surface normal. When it gets reflected from the mirror, it undergoes a deviation of

(a)40°
(b) 100°
(c) 90°
(d) 80°
Ans: (d)

CDS (II) 2017

140. The wires are made having same length l and area of crosssection
A. Wire 1 is made of copper and wire 2 is made of aluminium. It is given that the electrical conductivity of copper is more than that of aluminium. In this context, which one of the following statements is correct?

(a)The resistance of wire 1 will be higher than that of wire 2.
(b) The resistance of wire 2 will be higher than that of wire 1.
(c) The resistance of both the wires will be the same.
(d) If same current is flown through both the wires, the power dissipated in both the wires will be the same.
Ans: (b)

CDS (I) 2015

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