Which of the statements are correct indicate with a C and wh

Which of the statements are correct (indicate with a C) and which are incorrect (indicate with an I)? a) To correct for far sightedness a diverging (concave) lens is used to put the image of an object located at 25 cm at the near point. b) An object placed at the focal point of a convex mirror will not produce an image. c) A block of unknown index of refraction is submerged in Jello with index n = 1.4. A light ray in the block is incident on the block-Jello surface and bounces as shown. From this we know the block must have an index of refraction greater than Jello. d) The refractive power of glasses with a focal length of 43 cm is approximately 2.4 diopters. e) A source of unpolarized light is located at point If the intensity of light at point C is 1/4 that of the light at point A, the axes of polarization of the polarizers are at 45 degree with respect to each other. The network shown is assembled with uncharged capacitors with C_X = 2 mu F, C_Y = 3 mu F and C_Z = 1 mu F, and open switches. S_1 and S_2. A potential difference V_ab = +120V is applied between points a and After the circuit is assembled switch S_2 is closed then S_1 is closed. The total energy stored in this circuit is: a) 0.022 J b) 0.053 J c) 0.011 J d) 0.026 J e) 0.005 J

Solution

The option is incorrect as to correct farsightedness, convex lenses are prescribed. A convex mirror produces a virtual image always. So, no matter where the object is placed, a virtual image will be formed. So, this option is incorrect. Yes, this option is correct. As when the refractive index of block is greater than that of jello the refracted ray bends away from the normal until a critical value of refractive index when the refracted ray is along the interface boundary and beyond that, the ray gets almost completely reflected. This option is correct as P=100/f(in cm). This gives the power to be approximately 2.4 D This option is correct as if the polarization axes is at 90 degrees, no light will pass. Similarly, at 45 degrees intensity reduces to half and since there are 2 polarizers, intensity reduces to 0.25 times.