"To be" and its functions. "To have" and its functions

Make up all possible kinds of questions:

1. 
   A direct current flows only in one direction.
   
2. 
   The heating effect of current is independent of the direction of the current.
   
3. 
   The magnetic field varied with the moving coil current.
   
4. 
   Wattmeters always contain 2 electrical circuits.
   
5. 
   We shall briefly consider various kinds of electrical instruments.
   

IV. Translate the sentence, state the tense and the voice of the verbs:

1. 
   The measurement of an electric current is based upon its magnetic or heating effects.
   
2. 
   The action of thermal ammeters depends upon the heating effect of the current in them.
   
3. 
   Wattmeters are rarely used in D.C. circuits, because the power in them can be obtained from ammeter and voltmeter readings.
   
4. 
   The application of this principle will be dealt with later.
   
5. 
   An instrument which measures the energy consumed in an electric circuit is generally known as a meter.
   
6. 
   The unit of resistance is defined from relation between the difference of potential and the current that flows in a conductor.
   
7. 
   These quantities were converted from the physical variables of the problem.
   
8. 
   The analog computer variables are measured rather than counted on digital computers.
   
9. 
   Some current transformers consist of an iron core and a secondary winding, and the main current is carried by a straight conductor.
   
10. 
    If a tube has a trouble, it stops operating or operates badly and should be replaced by another one.
    
11. 
    To eliminate this counter flow, a third grid was placed between the plate and screen grid and connected to the cathode.
    
12. 
    The intensity of the beam is controlled by the control grid.
    
13. 
    The high level of television became possible due to the development of modern means of communication.
    
14. 
    The new studio unit will be fitted with the most modern transistor devices.
    
15. 
    Computers will handle large amounts of information accurately and rapidly.
    
16. 
    Hand operations are replaced by those that require little human assistance.