Questão 1
Questão
A chemical reaction takes place when water is put to a boil passing electricity through a heater immersed in the water.
Questão 2
Questão
during a chemical reaction, energy:
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is taken in
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is given out
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remains the same
Questão 3
Questão
When reactants are mixed,energy is used for ______ the molecules of the reactants into ________
Questão 4
Questão
the atoms ____ themselves to form the products
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rearrange
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recombine
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break
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divide
Questão 5
Questão
If the amount of energy required to break the atoms up is 250 and the the amount of energy released when atoms recombine is 300,what is the amount of energy exchanged with the surroundings?
Questão 6
Questão
A chemical reaction is used to describe a chemical equation
Questão 7
Questão
No atoms are created or destroyed in a chemical reaction
Questão 8
Questão
At room temperature gold is _____,water is _____ and oxygen is ________
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solid...liquid...gas
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gas...liquid...solid
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liquid....gas...solid
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liquid...solid...gas
Questão 9
Questão
Atoms and molecules are said to be in a constant______
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motion
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arrangement
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order
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state
Questão 10
Questão
in a solid the atoms are:
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packed closely together in a regular pattern
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move around eachother
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held and spun around in fixed positions
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have weak attractive forces
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have strong attractive forces
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have a definite shape and volume
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does not have a fixed volume
Questão 11
Questão
If a solid is heated the particles_____________________________________________________
Questão 12
Questão
in a liquid the atoms are arranged in a fixed pattern
Questão 13
Questão
liquids can flow because:
Questão 14
Questão
in a gas the atoms are:
Questão 15
Questão
solid to gas is the process of ________
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boiling
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sublimation
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freezing
Questão 16
Questão
electricity is produced by flow of
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electric charges
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electric current
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atoms
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energy
Questão 17
Questão
conventional current is the flow of electric charges from the _______ end to the ________ end
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positive.....to negative
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negative.....to positive
Questão 18
Questão
Electric current is defined as:
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the rate of flow of electric charges
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the rate of flow of electric current
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the rate of flow of electricity
Questão 19
Questão
the SI unit for electricity is ampere (A)
Questão 20
Questão
electric currents are measured by
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ammeters
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voltmeters
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generators
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cellphones
Questão 21
Questão
Ammeters must be connected in parallel
Questão 22
Questão
ammeter may get damaged if
Questão 23
Questão
electric circuits can be divided into two main categories:
Questão 24
Questão
An electric circuit is a path along which electric charges move
Questão 25
Questão
A series circuit forms a double loop
Questão 26
Questão
the current flowing through each electrical component in a series circuit is _____
Questão 27
Questão
disadvantage of series circuit is that there is less current flowing in each branch rather than that flowing out of the circuit
Questão 28
Questão
what is a parallel circuit?
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A circuit that splits into two or more branches
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A circuit that forms a single loop
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A circuit with multiple batteries
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A colorful circuit with balloons
Questão 29
Questão
Advantage of Parallel circuit is that the current flowing through each component is same.
Questão 30
Questão 31
Questão
the force needed to push electric charges round a circuit is supplied by:
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a battery
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an electric cell
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a bulb
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a toy
Questão 32
Questão
the amount of energy supplied by a source of electrical energy to each unit of electric charge is called ________
Questão 33
Questão
If more electric cells are connected in series,a ________ voltage will be obtained
Questão 34
Questão
Electrical energy is converted into light and heat when flowing through a bulb
Questão 35
Questão
SI unit of voltage is ______
Questão 36
Questão
The voltage of a source of electrical energy is called
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electromotive force
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potential difference
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energy
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cupcake
Questão 37
Questão
Resistors can only be added in series.
Questão 38
Questão
which of the following have heating elements inside them?
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hair dryer
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cellphone
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cranes
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toaster
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iron
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magnet
Questão 39
Questão
The heating element is usually made up of ________________
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nichrome wire
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conductor
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plastic
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coiled coil
Questão 40
Questão
In electro-plating the plating metal is connected to the __________ terminal
Questão 41
Questão
which of the following are uses of electromagnets
Questão 42
Questão
improper use of electricity can result in:
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electrocutions
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electric fires
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electric shocks
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dehydration
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high blood pressure
Questão 43
Questão
The consumer unit consists of damp conditions,main switch and electric bells.
Questão 44
Questão
some dangerous situations of using electricity are:
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damp conditions
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damaged insulation
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over-loading
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sleeping near it
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sitting on it
Questão 45
Questão
If it takes a 4kW kettle 10 minutes to boil the water in it,how much energy is used?
Calculate the cost of electricity if each unit costs 21 cents.
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2/3 kW and 14 cents
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1/3 kW and 6 cents
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1/2 kW and 21 cents