Gujarat Refinery English Medium School Physics Unit Test 1 2024-2025 PDF

GUJARAT REFINERY ENGLISH MEDIUM SCHOOL UNIT TEST 1 2024-2025 PHYSICS (CH- 1 and 2) STD: XII Sci. M. MARKS: 25 DATE: 29/07/24...

GUJARAT REFINERY ENGLISH MEDIUM SCHOOL UNIT TEST 1 2024-2025 PHYSICS (CH- 1 and 2) STD: XII Sci. M. MARKS: 25 DATE: 29/07/24 TIME: 45 min. PART – A  Choose the correct answer from the following (9) 1.Electric field line is a curve so that tangent drawn at every point gives ……. (a) only magnitude of electric field (b) only direction of electric field (c) magnitude and direction both (d) none of the above 2. For the points on the axis and equatorial plane of an electric dipole ----------- (a) V=0 on axis and V≠0 for equator (b) V=0 for both points (c) V≠ 0 for both points (c) V≠0 for axis , and V=0 for equator 3. Which physical unit does not represent electric potential? (a) −1 (b) (c) (d) −1 4. If an object having n1 electrons and n2 protons total charge on the object is ------- (a) ( 2 + 1) (b) ( 2 − 1) (c) ( 1 − 2) (d) ( 1 × 2) 5. Work done to bring an electron from one point to another point is 1.6x 10-16 J. What is the potential difference between two points? (a) 1 (b) 10 (c) 100 (d) 1000 6.The electric potential a t a point due to an electric dipole varies as …… (a) (b) (c) (d) r2 7. 5 nC and - 2 nC are placed at (2, 0, 0) cm and (x, 0, 0) cm. If potential energy of this system is -4.5 µJ, then x =......... cm. (a) I (b) 3 (c) 4 (d) 5 19 8. When 10 electrons are removed from a neutral metal plate through some process, the charge on it becomes. (a) –1.6 C (b) +1.6 C (c) 1019 C (d) 10–19 C 9. Force acting on a specific point in the uniform electric field by the charge 3.2 x 10-3 C is 0.128N Electric field at that point is---------------------------- N/C (a) 0.4 (b) 400 (c) 4000 (d) 40 PART – B Section - A  Question Nos. 10 to 12. Do as directed. Each question carries 2 marks (06) 10. Derive formula for the torque acting on an electric dipole in the uniform electric field. 11. A system has two charges qA = 2.5 × 10–7 C and qB = –2.5 × 10–7 C located at points A: (0, 0, – 30 cm) And B: (0,0, +30 cm), respectively. What is the total charge and electric dipole moment of the system? 12. Consider a uniform electric field E = 3 × 103 î N/C. (a) What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane? (b) What is the flux through the same square if the normal to its plane makes a 60° angle with the x-axis? Section - B  Question Nos. 13 and 14. Do as directed. Each question carries 3 marks (06) 13. Derive formula for electric field produced by a uniformly charge carrying very long wire at a distance r. 14. Two charges 3 × 10–8 C and –2 × 10–8 C are located 15 cm apart. At what point on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero. Section - C  Answer the following question as directed. (04) 15. Obtain equation for the electric field produced by an electric dipole on the equatorial plane of a dipole.