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Module 3 - Electricity Basics

 

1.   Electrical current is the rate of flow of  

 

electrons
protons
charge
volts

 

2.   Current =   

 

charge / time
potential difference / time
potential difference x Resistance
charge x time

 

3.   Potential difference = 

 

work done / time
work done / charge
work done / volt
work done / resistance

4.  A charge of 1.0 coulomb flows for 2 minutes, what is the current? Ampere

5.  A current of 100mA is flowing for 10 minutes, what is the charge passedCoulombs

6.  A current of 10mA passes a charge of 100 Coulombs.  How long is the supply switched on for? seconds

 

7.   Resistance  = 

 

Potential difference x current
current / potential difference
Potential difference / current
work done / current

8.  Consider this circuit


For the resistor network shown, calculate
a)      the total resistance of the combination    ohms

      b)      the p.d. across each resistor:               

      4ohm: V,  10 ohm: V,  20 ohm: V

c)      the current through each resistor.           

      4ohm: A,  10 ohm: A,  20 ohm: A

9.   For the circuit shown, calculate  
  a)    the total resistance of the circuit ohms
  b)      A
  c)      I1 A
 
d)      I2 A
 
e)      V1 V
 
f)      V2 V

 

 






10 For the circuit shown, calculate;

a)         the total resistance 
kilo-ohms
b)         the total current (I) 
A
c)         the branch currents (I1 and I2)
A and A
d)         the p.d. across resistor B 
V
e)         the p.d. across resistor D. 
V


 




 


 

11.   Energy   =  

 

Potential difference x current x time
Potential difference x time / current
Potential difference / current 
Potential difference x current

 

12.   Power   = 

 

Potential difference x current x time
Potential difference x time / current
Potential difference / current 
Potential difference x current

 

13.   Power   = 

 

resistance x  current squared
Potential difference x time squared
Potential difference / resistance squared 
current x resistance squared 

 

14. 

In the circuit shown, a d.c. supply of p.d. V and negligible internal resistance is connected to 400 W and 1600 W resistors arranged in series. 
A voltmeter of resistance 2000
W connected across the 400 W resistor gives a reading of 8.0 V.

Calculate:

    a)  the magnitude of the supply, 
 V
    

   b) and hence the p.d. across the 1600 W resistor      
 V  
    c) the p.d. across the 1600
W resistor when the voltmeter is disconnected.
     V
   

 

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