Practice Question answer set 1 - general science mcq Online Quiz (set-1) For All Competitive Exams

Q-1)   The number of images of an object placed between two parallel mirrors is

(a)

(b)

(c)

(d)

Q-2)   Find out the odd colour from the following options.

(a)

(b)

(c)

(d)

Q-3)   The heat required in calories to convert one gram of ice at 0°C to steam at 100°C is approximately

(a)

(b)

(c)

(d)

Q-4)   Sound waves do not travel in

(a)

(b)

(c)

(d)

Q-5)   Photosynthesis using the invisible part of the Sunlight is done by some

(a)

(b)

(c)

(d)

Q-6)   Consider the following statements for a simple harmonic motion:
  1. The magnitude of the velocity of the body is proportional to its displacement from the mean position.
  2. The magnitude of the acceleration of the body is proportional to its displacement from the mean position.
  3. The sum of the kinetic energy and potential energy of the body is always constant.
Which of the statements given above is/are correct?

(a)

(b)

(c)

(d)

Explanation:

Let the displacement (y) of a particle executing SHM at an instant be given by.

y = a sin (ωt + φ)

velocity, v = ${dy}/{dt}$ = aω cos(ω + φ)

Hence, the magnitude of the velocity of a body is not proportional to its displacement from the mean position.

Acceleration, A = ${dv}/{dt}$  = –aω2 sin (ωt + φ) = - ω2y

Hence, |A| ∝ y

The total energy in SHM is given by

E = PE + KE = EP + EK = 1/2 mω2a2 = a constant

Q-7)   When pressure on piece of ice is increases its melting point

(a)

(b)

(c)

(d)

Q-8)   The turntable of a gramophone is rotated at a constant speed of x revolutions/minute. Which one of the following values of the revolutions per minute is not used ?

(a)

(b)

(c)

(d)

Q-9)   When a glass rod is placed in steam, its length increases but its width

(a)

(b)

(c)

(d)

Q-10)   Consider the following statements:
  1. Speed of wave = $\text"wave length"/\text"time period"$.
  2. Wavelength is the distance between two nearest particles in phase.
  3. The flash of lightening is seen before the sound of thunder is heard.
  4. Speed of sound is greater than speed of light.
Which of the statements given above are correct?

(a)

(b)

(c)

(d)

Explanation:

Speed of sound at NTP = 332 m/s,

whereas speed of light is 3 × 108