# ICSE Class 10th Physics 4 – Electricity and Magnetism MCQs

#### Electric current is measured in ____.

Electric current is measured in ampere.

#### A current is flowing through a wire. Then the nature of the wire is ____.

Current is the rate of flow of electrons through a wire. The total number of electrons is always equal to the number of protons, when current flows in a wire. Thus, the wire is electrically neutral.

#### If the electric current through a conductor is doubled, then the amount of heat generated per second in the conductor is ____

The heat generated by a current carring conductor is directly proportional to the square of the current when resistance and time are constant. H ∝ i^{2} Hence, if the electric current through a conductor is doubled then the amount of heat generated per second in the conductor is quadrupled.

#### ____ material is used to prepare the filament of a bulb.

The material used to prepare filament of a bulb should have high resistance and high melting point. Tungsten has high resistance and high melting point; hence, it is used to prepare the filament of a bulb.

#### The property of a body to oppose the flow of electric charge through it is called electric ____.

Electric resistance is the property of a body due to which it oppose or resist the flow of electric charge through it.

#### In ____ negatively and positively charged ions free to move constitute current.

In both electrolytes and gases, negatively and positively charged ions free to move constitute current.

#### When number of resistors are connected in parallel, the resultant resistance of the combination is ____.

When number of resistors is connected in parallel, the reciprocal of the resultant resistance of the combination is the sum of the reciprocals of all the resistances. Hence, the resultant resistance of the combination is less than the least.

#### Joule's law of heating effect of electricity establishes a relation between ____.

According to Joule's law of heating effect, the amount of heat produced in a conductor is equal to the product of the square of the current, resistance of the conductor and the time for which current passes through the conductor.

#### 1 kW h is equivalent to ____.

1 kW h is equivalent to 3600000 J.

#### Resistance of a metallic conductor does not depend on its ____.

Resistance of a conductor is directly proportional to its length and inversely proportional to its area of cross-section. It also depends on the nature of the material. Resistance of a metallic conductor does not depend on its mass.

#### The heat generated by current carrying conductor does not depend upon the ____.

Heat generated by an electric current is directly proportional to the strength of the current and resistance. As resistance depends upon the length and area of cross section of the wire. Hence, it does not depend upon mass of the wire.

#### Electric current is defined as the rate of flow of ____.

Electric current is defined as the rate of flow of electric charge.

#### Which of the following is the purpose of connecting a battery in an electric circuit?

Battery is the source of energy. It is used to maintain constant potential difference across the conductor.

#### If the area of cross-section of a conductor is doubled, then its resistance will ____.

The resistance of a conductor is inversely proportional to its area of cross-section. Hence, if the area of cross-section of a conductor is doubled, its resistance is halved.

#### When the pendulum bob is in the mean position, total energy will be minimum.

When the pendulum bob is in the mean position, the total energy will remain unchanged. Total energy is the sum of KE and PE. At mean position, the KE is maximum and PE is zero. Hence, the total energy remains unchanged.

#### Resistance offered by the conductors does not depend on ____ of the conductor.

Resistance of a conductor depends on its length, area of cross-section and temperature. It does not depend on the surface area of the conductor.

#### Watt hour is called as ____.

When a current of one ampere flows through a conductor at a potential difference of 1 V, it is also called as volt-ampere hour, because for one hour.

#### Ohm's law gives the relation between potential difference and ____.

According to Ohm's law - At constant temperature, the current flowing through a conductor is directly proportional to the potential difference applied across its ends. It relates the potential difference and current.

#### Two bulbs A and B are connected in series with a cell. Resistance of the bulb A is R_{a} and resistance of the bulb B is R_{b}. The ratio of the currents in the bulb A to the bulb B is ____.

In a series circuit there is only one pathway where charge can traverse. Hence, strength of electric current is same in all the resistors.

#### Ammeter is a device that is used to measure ____.

Ammeter is a device used to measure electric current.

#### One horsepower (hp) is equivalent to ____.

Commercial unit of power is horsepower (hp). 1 horsepower is equal to 746 watt.

#### When number of resistors are connected in series, the resultant resistance of the combination is ____.

When number of resistors is connected in series, the resultant resistance of the combination is the sum of all the resistances. Hence, the resultant resistance of the combination is greater than the greatest.

#### A parallel combination of resistors is used to obtain a ____.

When two or more resistors are connected in parallel, the net resistance of the combination is smaller than the least resistance in the combination. Hence, a parallel combination of resistors is preferred to obtain a smaller resistance with a given set of resistors.

#### The commercial unit of electric energy is ____.

The commercial unit of electric energy is kilowatt hour.

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