19 June 2013

VIII Science Chapter-14-Chemical Effects Of Current

CBSE NCERT 8th (VIII) Science Chapter-14-Chemical Effects Of Current
Solved Questions for formative and summative assessments [FA+SA]
Class 8th to 12th
Q. What is electricity?
Answer: Electricity is a phenomenon known for its effect like chemical effect, Heating effect and magnetic effect.
Q. What is the cause of electricity?
Answer: The flow of charge is the main cause of electricity.
Q. What is charge?
Answer: The fundamental properties of matter caused by gain or loss of electrons.SI unit of charge is Coulomb or C
Q. What is the charge on 1 electron?
Answer: 1.6 x 10-19C
 Q. How many electrons present in 1 coulomb charge?
Answer: Q = n e Þ n  = (1C)/(1.6x10-19C) = 6x1018 electrons
Q. What are the two types of electricity on the basis of charge?
Answer: the two types of electricity on the basis of charge are:
(a) Static electricity: The electricity cause by the charge at rest.
(b) Current electricity: The electricity cause by the charge when in motion
Q. What is the cause of the flow of charge?
Answer: Electric potential or potential difference is the main cause of electric charge.
Q. What do you mean by chemical effect of current?
Answer: The phenomenon of causing chemical change by passing electric current through a conduction solution is called chemical effect of current. For example: Electrolysis and Electroplating
Q. What do you mean by heating effect of current?
Answer: Whenever current flows through a conductor it causes heating of material. This effect of current is known as heating effect of current.
Q. What do you mean by magnetic effect of current?
Answer: Whenever current flows through a conductor it behaves like a magnet. This effect of current is known as magnetic effect of current.
Q. What is LED?

Answer: LED stands for Light Emitting Diode. LED glows even when a weak electric current flows through it.
Q. What precaution you should take to add LED in a circuit?

Answer: The longer lead is always connected to the positive terminal of the battery and the shorter lead is connected to the negative terminal of the battery.

CBSE Class VIII Science
Chemistry       
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