Three equal resistors connected in series with a source of e m f together dissipate 10 W of power each. What will be the power dissipated if the same resistors are connected in parallel across the same source of e m f ?

Related Mcqs:

1. n an LCR series circuit, if V is the effective value of the applied voltage VR is the voltage across R VL is the effective voltage across L & Vc is the effective voltage across C then_______________?

   IA. V = VR+VL+VC
   B. V2 = VR2+VL2+VC2
   C. V2 = VR2+(VL-VC)2
   D. V2 = VL2+(VR-VC)2

2. Three bulbs are rating 40W 60W and 100W designed to work on 220V mains. Which bulb will burn most brightly if they are connected in series across 220 V mains ?

   A. 40 W bulb
   B. 60 W blub
   C. 100 W blub
   D. all will burn equally brightly

3. A voltage V = V0 cos ωt is applied across a resistor of resistance R the average power dissipated per cycle in the resistor is given by___________?

   A. V√/√2R
   B. V/√2√R
   C. V02/√2R
   D. 2/√2√R

4. When a pure inductor of inductance L and a pure capacitor of capacitance C are connected in parallel to a sinusoidal potential difference V the potential difference across both L & C will be_______________?

   A. Same
   B. Different
   C. At L will be more than at C
   D. At L will be less than at C

5. All electrical appliances are connected in parallel to each other between the main line and neutral wire to get ______________________?

   A. same current
   B. same current and potential difference
   C. different current but same potential difference
   D. different current and potential differences

6. A 10Ω electric heater is connected to a 220V 50Hz mains supply. What is the peak value of the potential difference across the heater element ?

   A. 220V
   B. 220/ 2V
   C. 110V
   D. 220 √2V

7. A 100µF capacitor with a 12V source in series having frequency 50Hz will offer a capacitive reactance of about______________?

   A. 32Ω
   B. 62Ω
   C. 50Ω
   D. 100Ω

8. The average power and instantaneous power become equal if work is done at __________________?

   A. any rate
   B. at variable rate
   C. at uniform rate
   D. at high rate

9. At resonance the value of the power factor in an L-C-R series circuit is_______________?

   A. Zero
   B. 2
   C. 1
   D. Not definite

10. The resultant of two forces of equal magnitudes is also equal to the magnitude of the forces. The angle between the two forces is________________?

    A. 30°
    B. 60°
    C. 90°
    D. 120°