A 110 V direct current motor generates a back-emf of 98 V when it runs at full speed. If the resistance of the coil of the motor is 10 W, the current which flows through it is

1. A 110 V direct current motor generates a back-emf of 98 V when it runs at full speed. If the resistance of the coil of the motor is 10 W, the current which flows through it is
2. A solenoid of length 15.0 cm with 2500 turns is placed coaxially in side the solenoid. The solenoid is a coil of cross sectional area 4.2 cm² which has 50 turns. What is the mutual inductance of the arrangement?
3. Two focal lens of focal length 10 cm and 30 cm respectively are separated by a distance An object at 16 cm, with a height of 11 cm is placed behind lens 1. Find
   1. distance of final image of the object from lens 2.
   2. height and orientation of the final image.
4. A single light ray (50° angle) travel through four medium with refractive index of 1.00 (medium A), 1.60 (medium B), 1.20 (medium C) and d (medium D). The arrangement of the experiment is shown if figure below. Find
   1. angle
   2. angle
   3. refractive index d medium D, if the refracted angle  is 30°
   4. refractive index d medium D, if the refracted angle  is 50°
5. Three point charges , and  are fixed at their respective positions as shown in the figure below.
   1. calculate the resultant force on charge .
   2. calculate the resultant force on charge , if .
6. 1. A uniformly charged disk like has a radius 1.5cm and carries a total charge of 5pC.

   Find

   Figure 4

   1. the electric field (magnitude and direction) on the x-axis at 15cm
   1. the electric field (magnitude and direction) on the x-axis at 15cm (point P), if there is another uniformly charged disk 20cm on the right of point P, with charge 6pC.
   2. A sheet of a rectangle shape with lengths 20cm and 0.3m, is immersed in a uniform electric field of magnitude 75N/C. The electric field is directed at 30° from flat sheet as shown in the figure below. Find the electric flux through the sheet.
7. 1. A capacitor (in vacuum) with different plate dimensions is shown in figure below, is aligned at P. The distance between plates is 6mm. Find

   ()

   Figure 7

   1. capacitance of the capacitor
   2. charge of the capacitor if the top plate potential, V=+3V and the bottom plate potential is V=+1.5V.
   3. new capacitance when a Teflon (dielectric constant, K = 2.1) is placed between the plate
   4. 1. Calculate the equivalent capacitances of the arrangements shown in the diagram.
         1.  

      Figure 8

       

      1.  
      Figure 9                                                    
   5. Figure below shows an electric circuit with a battery connected to multiple resistor. Find
      1. total resistance in the circuit
      2. current (I) flow through resistor N
      3. voltage drop across resistor P
      4. new resistor P, if voltage drop across Q is 1.5V ()
8. A 100cm copper wire is shown in the figure below. The resistivity of the wire is, . Find
   1. radius of the wire, r, if the resistance of the wire is 0.5Ω
   2. power generated in the wire, if the voltage across the wire is 2V

1. The voltage generated by a generator is as shown in the graph. Find

Figure 15

1. peak voltage
2. rms voltage
3. period

frequency                    

1. Figure below shows an AC circuit with resistor, , capacitor, , and inductor, . Find

Figure 16

1. total impedance of the circuit
2. voltage across resistor R
3. frequency resonance for the circuit

1. It is given that the mass of an atom of is 55.9349 u. Calculate the mass defect and binding energy. (mass of one electron, u, mass of one proton, u, mass of one neutron, u)

(4 marks)

1. Calculate the binding energy of , if the mass of is 26.981538 u.

 (2 marks)

1. A radioisotope tracer was injected into the human body. After 24 hours, the activity of the radioisotope has reduced to 6% of its initial activity. Calculate the half-life of the radioisotope.

 (2 marks)

1. The graph represents tha decay of a sample of a radioactive isotope.

Figure 17

Calculate the half-life of the isotope.