General Science Class 7th MCQs=836

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• The flow of electron is called current.     I=Q/t 
• The unit of current is amperes or amps.
• The complete path for the flow of current through the wire the cell and the filament of the bulb are called circuit.
• A series circuit provides one path for the current flow in the circuit.
• Parallel circuit provides separate paths for the current flow.
• An electric circuit is a complete unbroken path through which electric current can flow, such a circuit is called closed circuit.
• When there is no break in a circuit, no electric current is flow; such type circuit is called open circuit.
• A light bulb transforms electric energy to light energy.
• A radio and electric bells transforms electric energy to sound energy.
• A fan converts electric energy into mechanical energy.
• The chemical effect of current is used (1) In electroplating   (2) In the extraction of metal    (3) In the purification of metals.
• The difference in electrical potential of the charge is called the potential difference or voltage.
  
• The difference in electrical potential is called voltage (V) and is expressed as work done (W) per unit charge (Q).  V=    W/Q
  
• The unit of voltage is volt.
• Alessandro Volta who invented the first chemical battery.
  
• The opposition to the flow of current is called resistance.
  
• Resistance is represented by “R” and measure in ohms (Ω).
  
• A component which is used to close or break a circuit is called switch.
• A component which provides resistance is called resister.
  
• The relationship between voltage, current, and resistance according to Ohm’s law………………   
• Voltage (V) = Currant (I)  ×  Resistance (R)
• An ammeter is the device to measure the amount of current.
  
• Voltmeter is a device which is used for measuring voltage.
  
• Miniature circuit breakers (MCB) is automatically switches off the electrical circuit during abnormal condition of the network.
• A fuse is a safety device of a thin wire having low melting point which melt and breaks the circuit.

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A fuse is used to………………………..
a) Prevent electrical flow                      
b) Save electrical energy                
c) Prevent excessive currant                
d) Increase voltage

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The earth wire………………………….
a) Prevent excessive current flow          
b) Prevent electrical shocks           
c) Prevent the appliance from exploding      
d) Protect the appliance from floating voltage

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Charge in motion produces…………….
a) Current       
b) Voltage             
c) Circuit                     
d) Energy

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Current represent by symbol ………..
a) C     
b) Q                
c) I      
d) Cu

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The unit of current is ……...
a) amperes                  
b) volt
c) resistance                 
d) none of these

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