[{"id":126199,"question":"In order to observe interference , the interfering beams must be","choices":[{"text":"monochromatic","value":"A"},{"text":"coherent","value":"B"},{"text":"either of them","value":"C"},{"text":"both of them","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":126198,"question":"A monochromatic source of light gives light of","choices":[{"text":"one colour","value":"A"},{"text":"two colours","value":"B"},{"text":"four colours","value":"C"},{"text":"seven colours","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":126197,"question":"Light waves produce interference when","choices":[{"text":"source are monochromatic","value":"A"},{"text":"source are phase coherent","value":"B"},{"text":"sources are close together","value":"C"},{"text":"all of them","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":126196,"question":"When two light waves travelling in the same direction are out of phase at any point, their resultant amplitude","choices":[{"text":"increases","value":"A"},{"text":"decreases","value":"B"},{"text":"remains unchanged","value":"C"},{"text":"increases rapidly","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":126195,"question":"When the light waves of the same frequency and amplitude travelling in the same direction superimose each other , they give rise to","choices":[{"text":"interference","value":"A"},{"text":"diffraction","value":"B"},{"text":"dispersion","value":"C"},{"text":"polarization","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":126194,"question":"When two lights waves travelling in the same direction are in phase at any point, they producing","choices":[{"text":"constructive interference","value":"A"},{"text":"destructive interference","value":"B"},{"text":"dispersion","value":"C"},{"text":"polarization","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":126193,"question":"The medium in which speed of light is the same in all directions is called","choices":[{"text":"non-homogeneous medium","value":"A"},{"text":"homogeneous medium","value":"B"},{"text":"both of them","value":"C"},{"text":"empty medium","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":126192,"question":"According to the Huygen's principle, the secondary wavelets propagate in the forward direction with a speed equal to","choices":[{"text":"speed of wave motion","value":"A"},{"text":"speed of medium","value":"B"},{"text":"speed of electrons","value":"C"},{"text":"speed of protons","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":126191,"question":"Huygen's principle is used to study the","choices":[{"text":"formation of wavefronts","value":"A"},{"text":"propagation of wavefronts","value":"B"},{"text":"nature of light","value":"C"},{"text":"speed of light","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":126190,"question":"The wave nature of light was first proposed by","choices":[{"text":"Huygen","value":"A"},{"text":"Thomas Young","value":"B"},{"text":"Newton","value":"C"},{"text":"Compton","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":126189,"question":"According to Huygen's principle, the new position of the wavefront after a time can be found by constructing a surface that touches all the","choices":[{"text":"primary wavelets","value":"A"},{"text":"secondary wavelets","value":"B"},{"text":"either of them","value":"C"},{"text":"none of them","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":126188,"question":"According to Huygen's principle, every point of a wavefront may be considered as a source of","choices":[{"text":"primary wavelets","value":"A"},{"text":"secondary wavelets","value":"B"},{"text":"either of them","value":"C"},{"text":"both of them","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":126187,"question":"By which principle we can locate the position of new wavefront after a later time?","choices":[{"text":"principle of irreversibility","value":"A"},{"text":"principle of light","value":"B"},{"text":"Archimedes principle","value":"C"},{"text":"Huygen's principle","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":126186,"question":"A usual way to obtain a plane wave is to place point source of light at the focus of a","choices":[{"text":"concave lens","value":"A"},{"text":"convex lens","value":"B"},{"text":"both of them","value":"C"},{"text":"either of them","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":126185,"question":"In the study of interference and diffraction, we consider","choices":[{"text":"plane waves","value":"A"},{"text":"plane wavefronts","value":"B"},{"text":"both of them","value":"C"},{"text":"none of them","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":126184,"question":"The light form Sun reaches earth in the form of","choices":[{"text":"plane wavefront","value":"A"},{"text":"circular wavefront","value":"B"},{"text":"spherical wavefront","value":"C"},{"text":"elliptical wavefront","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":126183,"question":"A limited region taken on a wavefront which is far away form the source is","choices":[{"text":"plane wavefront","value":"A"},{"text":"circular wavefront","value":"B"},{"text":"spherical wavefront","value":"C"},{"text":"elliptical wavefront","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":126182,"question":"The distance between the concentric wavefronts is","choices":[{"text":"half wavelength","value":"A"},{"text":"one wavelength","value":"B"},{"text":"one and a half wavelength","value":"C"},{"text":"none of them","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":126181,"question":"The waves propagate in space by the motion of the","choices":[{"text":"wavelengths","value":"A"},{"text":"frequencies","value":"B"},{"text":"wavefronts","value":"C"},{"text":"none of them","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":126180,"question":"A line normal to the wavefront including the direction of motion is called","choices":[{"text":"perpendicular line","value":"A"},{"text":"parallel line","value":"B"},{"text":"a ray of light","value":"C"},{"text":"none of them","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":126179,"question":"In case of a point source, the shape of the wavefront is","choices":[{"text":"straight","value":"A"},{"text":"elliptical","value":"B"},{"text":"oval","value":"C"},{"text":"spherical","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":126178,"question":"Such a surface on which all the points have the same phase of vibration is known as","choices":[{"text":"wavefront","value":"A"},{"text":"amplitude","value":"B"},{"text":"displacement","value":"C"},{"text":"all of them","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":126177,"question":"Which characteristics of wave, established the Huygen's wave theory in 1801?","choices":[{"text":"polarization","value":"A"},{"text":"interference","value":"B"},{"text":"propagation","value":"C"},{"text":"all of them","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":126176,"question":"The experimental evidence in support of wave theory in Huygen's time was","choices":[{"text":"not present","value":"A"},{"text":"not convincing","value":"B"},{"text":"convincing","value":"C"},{"text":"none of them","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":126175,"question":"Who proposed that light energy form a luminous source travels in space by means of wave motion?","choices":[{"text":"Newton","value":"A"},{"text":"Maxwell","value":"B"},{"text":"Einstein","value":"C"},{"text":"Huygen","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":121405,"question":"The ratio of kinetic energy to potential energy for solids is","choices":[{"text":"","img":"121405_636345096369614057-RA1.jpg","value":"A"},{"text":"","img":"121405_636345096369614057-RA2.jpg","value":"B"},{"text":"","img":"121405_636345096369614057-RA3.jpg","value":"C"},{"text":"","img":"121405_636345096369614057-RA4.jpg","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":121404,"question":"Which of the following pairs is not correct","choices":[{"text":"Strain - dimensional","value":"A"},{"text":"Stress - N/m<sup>2</sup>","value":"B"},{"text":"Modulus of elasticity - N/m<sup>2</sup>","value":"C"},{"text":"Shear stress - N/m<sup>2</sup>","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":121403,"question":"Which of the following is not dimension less","choices":[{"text":"Poission ration","value":"A"},{"text":"Sharing strain","value":"B"},{"text":"Longitudinal strain","value":"C"},{"text":"Volume stress","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":121401,"question":"The modulus of elasticity of material does not depend upon","choices":[{"text":"Shape","value":"A"},{"text":"Temperature","value":"B"},{"text":"Nature of material","value":"C"},{"text":"Impurities mixed","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":121398,"question":"Longitudinal strain can be produced in","choices":[{"text":"Glass","value":"A"},{"text":"Water","value":"B"},{"text":"Honey","value":"C"},{"text":"Hydrogen gas","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":121396,"question":"If the tensile force is suddenly removed from a wire then its temperature will","choices":[{"text":"Decrease","value":"A"},{"text":"Increase","value":"B"},{"text":"Become zero","value":"C"},{"text":"Remain constant","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":121394,"question":"The Hook's law defines","choices":[{"text":"Modulus of elasticity","value":"A"},{"text":"Stress","value":"B"},{"text":"Strain","value":"C"},{"text":"Elastic limit","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":121391,"question":"The shearing strain is measured by","choices":[{"text":"Angle of rotation","value":"A"},{"text":"Shearing stress","value":"B"},{"text":"Angle of shear","value":"C"},{"text":"Modulus of rigidity","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":121389,"question":"If S is the stress and Y is Young's modulus of the material of a wire, the energy stored in the wire per unit volume is","choices":[{"text":"2 S<sup>2</sup>Y","value":"A"},{"text":"S<sup>2</sup>/2Y","value":"B"},{"text":"2Y/S<sup>2</sup>","value":"C"},{"text":"S/2Y","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":121387,"question":"","questionImage":"121387_636345088101130109-RQ.jpg","choices":[{"text":"","img":"121387_636345088101130109-RA1.jpg","value":"A"},{"text":"","img":"121387_636345088101130109-RA2.jpg","value":"B"},{"text":"","img":"121387_636345088101130109-RA3.jpg","value":"C"},{"text":"","img":"121387_636345088101130109-RA4.jpg","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":121377,"question":"On applying a stress of 20 x 10<sup>8</sup>Nm<sup>-2</sup>, the length of perfectly elastic wire is doubled. Its young' modulus is","choices":[{"text":"40 x 10<sup>8 </sup>N/m<sup>2</sup>","value":"A"},{"text":"20 x 10<sup>8</sup>N/m<sup>2</sup>","value":"B"},{"text":"10 x 10<sup>8</sup>N/m<sup>2</sup>","value":"C"},{"text":"5 x 10<sup>8</sup>N/m<sup>2</sup>","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":121375,"question":"A certain force F increases the length of a wire by 1 mm. The force required to increase its length by 2mm is","choices":[{"text":"2 F","value":"A"},{"text":"4 F","value":"B"},{"text":"8 F","value":"C"},{"text":"16 F","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":121372,"question":"A bar of length L, cross-section A and Young's modulus Y, is pulled by a force F from both ends so as to produce an elongation x. Then:","choices":[{"text":"x<span style=\"color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 224);\"><i>∝</i></span>1/L","value":"A"},{"text":"x<span style=\"color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 224);\"><i>∝</i></span>A","value":"B"},{"text":"x<span style=\"color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 224);\"><i>∝</i></span>1/A","value":"C"},{"text":"x<span style=\"color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 224);\"><i>∝</i></span>Y","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":121369,"question":"The young's modulus of a wire of length L and radius 'r' is Y. If the length is reduced to L/2 and radius to r/2, its Young's modulus will be","choices":[{"text":"Y/2","value":"A"},{"text":"Y","value":"B"},{"text":"2Y","value":"C"},{"text":"4Y","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":121366,"question":"Energy per unit volume of a stretched wire is","choices":[{"text":"(1/2) x load x extension","value":"A"},{"text":"Load x stress","value":"B"},{"text":"Stress x strain","value":"C"},{"text":"(1/2) x stress x strain","value":"D"},{"value":"E"}],"correctAnswer":4}]