DHS 17 Electromagnetic Induction (Tutorial Answers)

Dunman High School (Senior High) H2 Physics (Syllabus 9749) Topic 17: Electromagnetic Induction Y6 2025 Tutorial Solutions 1 For Internal Use Only 1 During the rotation,  there is no change in magnetic flux density B passing through the coil  the change in total magnetic flux is given by:   ocos cos0 cos 1 , which is negative decreases f i BA BA BA           Answer: C 2 magnetic flux through the loop of wire:    6 4 2 o 8cos 65 10 T 12 10 m cos30 6.8 10BA          Answer: B B θ normal A normal θ

Dunman High School (Senior High) H2 Physics (Syllabus 9749) Topic 17: Electromagnetic Induction Y6 2025 Tutorial Solutions 2 For Internal Use Only 14 April 2025 3 magnetic flux density, B magnetic flux,  = BA = B × (8.0 × 10−3) magnetic flux linkage, N = 800  = 6.4B magnetic flux density / T magnetic flux / Wb magnetic flux linkage / Wb turns A 3.4 2.7 × 102  220  22 B 2.7 × 102 3.4  2.2 × 104 2700  0.173 C 3.4 × 104 4.2 × 102  2.7 × 106 34  2.2 × 103 D 4.2 × 102 3.4 × 104  0.27  Answer: D 4 B Since speed is constant, the change of flux linkage in entering and leaving the solenoid would take place over the same period of time, hence induced e.m.f. have the same maximum value. (Faraday’s Law) normal to area of coils of solenoid When the whole magnet remains well within the long solenoid, with the flux linkage being the maximum and remaining unchanged, the induced e.m.f. remains zero. (Faraday’s law) When magnet is entering and leaving the solenoid, the total change in flux linkage (area under the graph) is the same. 2 1 area under graph t t dN dt N dt t           N 

Dunman High School (Senior High) H2 Physics (Syllabus 9749) Topic 17: Electromagnetic Induction Y6 2025 Tutorial Solutions 3 For Internal Use Only 14 April 2025 i. first, the switch is closed ii. then the variable resistor in series with the cell is decreased iii. then the circuit containing resistor R is moved to the left iv. then the switch is opened. 5 D T/2 Since ߝ= − ௗேః ௗ௧ = − ௗ(ே஻஺) ௗ௧ = −ܣܰ ௗ஻ ௗ௧ , induced e.m.f is the largest when the gradient of the graph is the steepest.    0 0 0 cossin cos 2Note: 2 d B tdN dB NA NA NAB tdt