Page 1 Compartment Page No. 1 20 th July, 2014 Final MARKING SCHEME SET 55/1/3 (Compartment) Q.No. Expected Answer/Value Points Marks Total Marks 1. Random motion of free electrons gets directed towards the point at a higher potential. Alternatively: Random motion becomes a (partially) directed motion. 1 1 2. Two monochromatic sources, which produce light waves, having a constant phase difference, are known as coherent sources. 1 1 3. 1 1 4. Paramagnetic material 1 1 5. Effective power (Alternatively: Effective power radiated decreases with an increase in wavelength.) 1 1 6. Due to the heating effect of eddy currents set up in the metallic piece. 1 1 7. When a constant current flows through a wire, the Potential difference, between any two points on the wire of uniform cross section, is directly proportional to the length of the wire between these points. Alternatively: V or = constant 1 1 8. i. The two point charges( and ) should be of opposite nature. ii. Magnitude of charge must be greater than that of charge ½ ½ 1 9 ½ Drawing of magnetic field lines ½ Obtaining the expression for magnetic field 1 ½ Page 2 Compartment Page No. 1 20 th July, 2014 Final MARKING SCHEME SET 55/1/3 (Compartment) Q.No. Expected Answer/Value Points Marks Total Marks 1. Random motion of free electrons gets directed towards the point at a higher potential. Alternatively: Random motion becomes a (partially) directed motion. 1 1 2. Two monochromatic sources, which produce light waves, having a constant phase difference, are known as coherent sources. 1 1 3. 1 1 4. Paramagnetic material 1 1 5. Effective power (Alternatively: Effective power radiated decreases with an increase in wavelength.) 1 1 6. Due to the heating effect of eddy currents set up in the metallic piece. 1 1 7. When a constant current flows through a wire, the Potential difference, between any two points on the wire of uniform cross section, is directly proportional to the length of the wire between these points. Alternatively: V or = constant 1 1 8. i. The two point charges( and ) should be of opposite nature. ii. Magnitude of charge must be greater than that of charge ½ ½ 1 9 ½ Drawing of magnetic field lines ½ Obtaining the expression for magnetic field 1 ½ Compartment Page No. 2 20 th July, 2014 Final Alternatively: Applying Ampere circuital law for the rectangular loop abcd = Bh = (nh) B = ½ ½ ½ 2 10. (i) Intensity of incident radiation I = nhv, where n is number of photons incident per unit time per unit area. For same intensity of two monochromatic radiations of frequency and = As > ? Therefore the number of electrons emitted for monochromatic radiation of frequency , will be more than that for radiation of frequency [Alternatively: Also accept if the student says that, for same intensity of incident radiation, the number of emitted electrons is same for each of the two frequencies of incident radiation.] (i) hv = For given (work function of metal) increases with Maximum Kinetic energy of emitted photoelectrons will be more for monochromatic light of frequency as > ) ½ ½ ½ ½ 2 Explanation of parts (i) and (ii) 1+1 Page 3 Compartment Page No. 1 20 th July, 2014 Final MARKING SCHEME SET 55/1/3 (Compartment) Q.No. Expected Answer/Value Points Marks Total Marks 1. Random motion of free electrons gets directed towards the point at a higher potential. Alternatively: Random motion becomes a (partially) directed motion. 1 1 2. Two monochromatic sources, which produce light waves, having a constant phase difference, are known as coherent sources. 1 1 3. 1 1 4. Paramagnetic material 1 1 5. Effective power (Alternatively: Effective power radiated decreases with an increase in wavelength.) 1 1 6. Due to the heating effect of eddy currents set up in the metallic piece. 1 1 7. When a constant current flows through a wire, the Potential difference, between any two points on the wire of uniform cross section, is directly proportional to the length of the wire between these points. Alternatively: V or = constant 1 1 8. i. The two point charges( and ) should be of opposite nature. ii. Magnitude of charge must be greater than that of charge ½ ½ 1 9 ½ Drawing of magnetic field lines ½ Obtaining the expression for magnetic field 1 ½ Compartment Page No. 2 20 th July, 2014 Final Alternatively: Applying Ampere circuital law for the rectangular loop abcd = Bh = (nh) B = ½ ½ ½ 2 10. (i) Intensity of incident radiation I = nhv, where n is number of photons incident per unit time per unit area. For same intensity of two monochromatic radiations of frequency and = As > ? Therefore the number of electrons emitted for monochromatic radiation of frequency , will be more than that for radiation of frequency [Alternatively: Also accept if the student says that, for same intensity of incident radiation, the number of emitted electrons is same for each of the two frequencies of incident radiation.] (i) hv = For given (work function of metal) increases with Maximum Kinetic energy of emitted photoelectrons will be more for monochromatic light of frequency as > ) ½ ½ ½ ½ 2 Explanation of parts (i) and (ii) 1+1 Compartment Page No. 3 20 th July, 2014 Final 11. Total magnification = 1 1 2 12. Work done in bringing the charge from infinity to position Hence, total work done in assembling the two charges OR Work done in moving a unit positive charge along distance = = V â€“ (V + = - E= - (i) Electric field is in the direction in which the potential decreases steepest. (ii) Magnitude of Electric field is given by the change in the magnitude of potential per unit displacement, normal to the equipotential surface at the point. ½ ½ +½ ½ ½ ½ ½ ½ 2 2 Ray diagram of formation of image by a compound microscope 1 Expression for total magnification 1 Obtaining the expression for total work done 2 Derivation of relation between Electric field and potential gradient 1 Two important conclusions ½ + ½ Page 4 Compartment Page No. 1 20 th July, 2014 Final MARKING SCHEME SET 55/1/3 (Compartment) Q.No. Expected Answer/Value Points Marks Total Marks 1. Random motion of free electrons gets directed towards the point at a higher potential. Alternatively: Random motion becomes a (partially) directed motion. 1 1 2. Two monochromatic sources, which produce light waves, having a constant phase difference, are known as coherent sources. 1 1 3. 1 1 4. Paramagnetic material 1 1 5. Effective power (Alternatively: Effective power radiated decreases with an increase in wavelength.) 1 1 6. Due to the heating effect of eddy currents set up in the metallic piece. 1 1 7. When a constant current flows through a wire, the Potential difference, between any two points on the wire of uniform cross section, is directly proportional to the length of the wire between these points. Alternatively: V or = constant 1 1 8. i. The two point charges( and ) should be of opposite nature. ii. Magnitude of charge must be greater than that of charge ½ ½ 1 9 ½ Drawing of magnetic field lines ½ Obtaining the expression for magnetic field 1 ½ Compartment Page No. 2 20 th July, 2014 Final Alternatively: Applying Ampere circuital law for the rectangular loop abcd = Bh = (nh) B = ½ ½ ½ 2 10. (i) Intensity of incident radiation I = nhv, where n is number of photons incident per unit time per unit area. For same intensity of two monochromatic radiations of frequency and = As > ? Therefore the number of electrons emitted for monochromatic radiation of frequency , will be more than that for radiation of frequency [Alternatively: Also accept if the student says that, for same intensity of incident radiation, the number of emitted electrons is same for each of the two frequencies of incident radiation.] (i) hv = For given (work function of metal) increases with Maximum Kinetic energy of emitted photoelectrons will be more for monochromatic light of frequency as > ) ½ ½ ½ ½ 2 Explanation of parts (i) and (ii) 1+1 Compartment Page No. 3 20 th July, 2014 Final 11. Total magnification = 1 1 2 12. Work done in bringing the charge from infinity to position Hence, total work done in assembling the two charges OR Work done in moving a unit positive charge along distance = = V â€“ (V + = - E= - (i) Electric field is in the direction in which the potential decreases steepest. (ii) Magnitude of Electric field is given by the change in the magnitude of potential per unit displacement, normal to the equipotential surface at the point. ½ ½ +½ ½ ½ ½ ½ ½ 2 2 Ray diagram of formation of image by a compound microscope 1 Expression for total magnification 1 Obtaining the expression for total work done 2 Derivation of relation between Electric field and potential gradient 1 Two important conclusions ½ + ½ Compartment Page No. 4 20 th July, 2014 Final 13. P: NOT Gate Q: AND Gate Input A Output Y 0 1 1 0 NOT gate ½ ½ ½ ½ 2 14. Equivalent magnetic moment of the coil =IA =I b ( = unit vector to the plane of the coil) Torque = = I b = 0 (as are parallel or antiparallel, to each other) [Note: Also give credit, when student obtains the relation , and substitutes and writes ½ ½ ½ ½ 2 15. = As = 0 ? = ? = = ? wavelength ( )of emitted electrons, ½ ½ ½ ½ 2 Naming of gates P and Q ½ + ½ Truth Table of combination & Identification ½ + ½ Obtaining the expression for the torque 2 Finding the relation 1 ½ Drawing the graph ½ Page 5 Compartment Page No. 1 20 th July, 2014 Final MARKING SCHEME SET 55/1/3 (Compartment) Q.No. Expected Answer/Value Points Marks Total Marks 1. Random motion of free electrons gets directed towards the point at a higher potential. Alternatively: Random motion becomes a (partially) directed motion. 1 1 2. Two monochromatic sources, which produce light waves, having a constant phase difference, are known as coherent sources. 1 1 3. 1 1 4. Paramagnetic material 1 1 5. Effective power (Alternatively: Effective power radiated decreases with an increase in wavelength.) 1 1 6. Due to the heating effect of eddy currents set up in the metallic piece. 1 1 7. When a constant current flows through a wire, the Potential difference, between any two points on the wire of uniform cross section, is directly proportional to the length of the wire between these points. Alternatively: V or = constant 1 1 8. i. The two point charges( and ) should be of opposite nature. ii. Magnitude of charge must be greater than that of charge ½ ½ 1 9 ½ Drawing of magnetic field lines ½ Obtaining the expression for magnetic field 1 ½ Compartment Page No. 2 20 th July, 2014 Final Alternatively: Applying Ampere circuital law for the rectangular loop abcd = Bh = (nh) B = ½ ½ ½ 2 10. (i) Intensity of incident radiation I = nhv, where n is number of photons incident per unit time per unit area. For same intensity of two monochromatic radiations of frequency and = As > ? Therefore the number of electrons emitted for monochromatic radiation of frequency , will be more than that for radiation of frequency [Alternatively: Also accept if the student says that, for same intensity of incident radiation, the number of emitted electrons is same for each of the two frequencies of incident radiation.] (i) hv = For given (work function of metal) increases with Maximum Kinetic energy of emitted photoelectrons will be more for monochromatic light of frequency as > ) ½ ½ ½ ½ 2 Explanation of parts (i) and (ii) 1+1 Compartment Page No. 3 20 th July, 2014 Final 11. Total magnification = 1 1 2 12. Work done in bringing the charge from infinity to position Hence, total work done in assembling the two charges OR Work done in moving a unit positive charge along distance = = V â€“ (V + = - E= - (i) Electric field is in the direction in which the potential decreases steepest. (ii) Magnitude of Electric field is given by the change in the magnitude of potential per unit displacement, normal to the equipotential surface at the point. ½ ½ +½ ½ ½ ½ ½ ½ 2 2 Ray diagram of formation of image by a compound microscope 1 Expression for total magnification 1 Obtaining the expression for total work done 2 Derivation of relation between Electric field and potential gradient 1 Two important conclusions ½ + ½ Compartment Page No. 4 20 th July, 2014 Final 13. P: NOT Gate Q: AND Gate Input A Output Y 0 1 1 0 NOT gate ½ ½ ½ ½ 2 14. Equivalent magnetic moment of the coil =IA =I b ( = unit vector to the plane of the coil) Torque = = I b = 0 (as are parallel or antiparallel, to each other) [Note: Also give credit, when student obtains the relation , and substitutes and writes ½ ½ ½ ½ 2 15. = As = 0 ? = ? = = ? wavelength ( )of emitted electrons, ½ ½ ½ ½ 2 Naming of gates P and Q ½ + ½ Truth Table of combination & Identification ½ + ½ Obtaining the expression for the torque 2 Finding the relation 1 ½ Drawing the graph ½ Compartment Page No. 5 20 th July, 2014 Final 16. i. emf induced e = = 0.25 x 15 x 10 -2 x 25 = 0.9375 volt = 0.94 volt ii. Current in the loop i = = = 0.23 A ½ ½ ½ ½ 2 17. (ii) Conductor (ii) Semiconductor = In conductors, average relaxation time decreases with increase in temperature, resulting in an increase in resistivity. In semiconductors, the increase in number density (with increase in temperature) is more than the decrease in relaxation time; the net result is, therefore, a decrease in resistivity. ½ + ½ ½ ½ 2 18. Charge on inner surface : - Q Charge on outer surface : + Q Electric field at point E = ½ ½ 1 2 19. (i) In diffraction pattern, intensity will be minimum at an angle There will be a first minimum at an angle on either side of central maximum ½ Calculation of i. emf induced in the arm PQ 1 ii. Current induced in the loop 1 Drawing the two plots ½ + ½ Explanation of Behaviour ½ + ½ Charges on the inner and outer surfaces ½ + ½ Expression for electric field 1 Explanation of part (i) and (ii) 1 ½ + 1 ½Read More

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