Q1:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Silver is not used to make electric wires.
Reason : Silver is a bad conductor.
Explanation
Silver is a good conductor of electricity but it is not used to make electric wires because it is expensive.
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Q2:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : When the resistances are connected end- to-end consecutively, they are said to be in series.
Reason : In case the total resistance is to be increased, then the individual resistances are connected in series.
Explanation
- Current in a circuit depends on resistance as well as Potential Difference of the circuit.
- It is necessary to combine two or more resistances to get the required current in the electrical circuits
- Resistances can be combined in two ways: in series and in parallel.
- When two or more resistances are connected end to end consecutively, they are said to be connected in series.
- And on the other hand, when two or more resistances are connected between the same two points, they are said to be connected in parallel.
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Q3:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion: Tungsten metal is used for making filaments of incandescent lamps.
Reason : The melting point of tungsten is very low.
Explanation
Tungsten is selected for making filaments of incandescent lamp bulbs because tungsten can sustain high temperature and it has a high melting point, with high resistivity.
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Q4:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Alloys are commonly used in electrical heating devices, like electrical iron, toasters etc.
Reason : Alloys do not oxidise (burn) readily at high temperatures.
Explanation
An alloy generally has a higher resistivity than its constituent metals. Alloys do not oxidise (burn) readily at high temperatures. For this reason, they are commonly used in electrical heating devices, like electric iron, toasters etc.
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Q5:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : When a battery is short-circuited, the terminal voltage is zero.
Reason : In the situation of a short-circuit, the current is zero
Explanation
In the case of a short-circuited battery, the current
Terminal voltage, V = IR = I(i) = 7(0) = 0
Where, R = external resistance = 0
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Q6:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : When the resistances are connected between the same two points, they are said to be connected in parallel.
Reason : In case the resistance is to be decreased, then the individual resistances are connected in parallel.
Explanation
In parallel connection, all the elements are connected between the same two points hence the voltage drop across any number of resistors or other elements connected in parallel is the same.
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Q7:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : A resistor of resistance R is connected to an ideal battery. If the value of R is decreased, the power dissipated in the circuit will increase.
Reason : The power dissipated in the circuit will increase.
Explanation
The relation between power dissipation and resistance is given by
P = E2/R i.e Power dissipation is indirectly proportional to the resistance. Hence if the value of R is decreased, the power dissipation in the circuit will increase. Hence the assertion is correct. But the reason is incorrect as it mentions that the power dissipation is directly proportional to the resistance of the circuit which contradicts the relation between power dissipation and resistance of the circuit.
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Q8:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : The electric bulbs glow immediately when the switch is on.
Reason : The drift velocity of electrons in a metallic wire is very high.
Explanation
In a conductor there are large numbers of free electrons. When we close the circuit, the electric field is established instantly with the speed of electromagnetic waves which causes electron drift at every portion of the circuit. Due to which the current is set up in the entire circuit instantly. The current which is set up does not wait for the electrons to flow from one end of the conductor to another end. Due to this, the bulb glows immediately when the switch is on.
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Q9:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Long distance power transmission is done
Reason : At high voltage supply power losses are less.
Explanation
Power loss = [P = Transmitted power]
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Q10:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Insulators do not allow flow of current through themselves.
Reason : They have no free-charge carriers.
Explanation
Insulators are bad conductors because they don't have free charge carriers which will flow and hence the correct option becomes A.
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Q11:
Question for Assertion & Reason Type Questions: Electricity
Try yourself:Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : The equation V = RI does not apply to those conducting devices which do not obey Ohm’s law.
Reason : V= RI is mathematical representation of Ohm’s law.
Explanation
- The assertion states that the equation V = RI does not apply to devices not obeying Ohm's law. This is true because Ohm's law describes a linear relationship between voltage, current, and resistance.
- The reason states that V = RI is the mathematical representation of Ohm's law. This is also true, as Ohm's law is represented by this equation.
- While both statements are true, the reason does not directly explain why the equation doesn't apply to non-ohmic devices, making the correct choice B.
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Q12:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Heater wire must have high resistance and will be melting point.
Reason : If resistance is high, the electric conductivity will be less.
Explanation
Heater wire must have high resistance and high melting point, because in series current remains same, therefore according to Joule’s law, H= PR t, heat produced is high if R is high melting point must be high, so that wire may not melt with increase in temperature.
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Q13:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : A tube light emits white light.
Reason : Emission of light in a tube takes place at a very high temperature
Explanation
In tube light, the gas contains vapour of metals. In metallic atoms, electronic transition occurs due to which light of a particular wavelength is emitted. So emission of whit light is due to electronic transition and not due to vibration of atoms as in hot substance. SO, assertion is true but reason is false.
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Q14:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Bending a wire does not affect electrical resistance.
Reason : Resistance of wire is proportional to resistivity of material.
Explanation
Resistance of wire R =
Where p is resistivity of material which does not depend on the geometry of wire. Since when wire is bent, resistivity, length and area of cross-section do not change, therefore resistance of wire also remains same.
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Q15:
Question for Assertion & Reason Type Questions: Electricity
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : If a graph is plotted between the potential difference and the current flowing, the graph is a straight line passing through the origin.
Reason : The current is directly proportional to the potential difference.
Explanation
According to Ohm's law, the potential difference across a conductor is directly proportional to the current through it.
V=IR
Hence the curve is a straight line passing through the origin.
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[P = Transmitted power]
