Class 10 Science Chapter 11 MCQ

Explanation: Electric power is given by P = Voltage x Current SI unit of voltage = volt SI unit of current = Ampere So, its unit is volt ampere.

The SI unit of electric charge coulomb is equivalent to the charge contained in 6.25 x 10 to the power 18.

In series combination of resistances same current flows through each resistor where as in parallel combination same voltage exist across each resistor. Thus, the two resistors of resistances 2 Ω and 4 Ω are connected in series has same current flowing through it.

Here, all these statements are correct. Hence, your answer will be option [D].

Here, all these statements are correct. Hence, your answer will be option [D].

In an electrical circuit, three incandescent bulbs A, B and C of rating 40 W, 60 W, and 100 W are connected in parallel to and electrical source, then the bulb with the highest wattage glows with maximum brightness. Thus, the brightness of bulb B (100 W) is maximum. This brightness different bulks are in following order: B100 > B60 > B40

Current is measured by an instrument called ammeter. The ammeter is always connected in series with the circuit in which the current is to be measured.

Here, all these statements are correct. Hence, your answer will be option [D].

The current is directly proportional to the potential difference applied across the ends of a conductor it means that if the potential difference across the ends of a conductor is doubled, the current flowing through it also gets doubled, and if the potential difference is halved the current also gets halved.

As we know that: W= charge × potential difference W= Q × V As we know that Q= I × t Therefore, putting in above equation W= I × t × V V= Work done/ Current × time

Here, all these statements are correct. Hence, your answer will be option [D].

The minimum resistance is obtained when resistors are connected in parallel combination. This equivalent resistance will be: Rƿ = R/n = 1/5/5 = 1/25 Ω Rƿ = equivalent resistance for parallel combination.

The heating element of electric iron is made of nichrome wire which is a resistor. The electric wires are made of copper which is a good conductor but their covering is made of plastic which is an example of insulator.

The maximum resistance is obtained when resistors are connected in parallel combination. This equivalent resistance will be: Rs = n x R = 5 X 1/5 = 1Ω Rs = equivalent resistance for series combination.

If we take a lot of copper metal 1 metre long and 1 square metre in area of cross section then its resistance will be 1.69 x 10 to the power -8.

We know that, H = I²Rt It shows that the heat produced is proportional to the square of the current.

Nichrome does not undergo oxidation or burn easily even at high temperature. Due to this nichrome wire can be kept red hot without burning or breaking in air.

An electric fuse works on the heating effect of current.

Here, all these statements are correct. Hence, your answer will be option [D].

It is the temperature of an electric bulb filament when it glows.

1 kilowatt hour is equal to 3.6 X 10 to the power 6, joules of electrical energy. One kilowatt hour is the amount of energy consumed at the rate of 1 kilowatt for 1 hour. 1 kilowatt hour = 36,00,000 joules (or 3.6 X 10 to the power 6).

Energy transferred, E = power x time = 100 W x 60 s = 6000 J

This is so because in a parallel circuit, if one device fails, it does not affect the working of the other devices.

If the resistance wire is cut into five pieces, the resistance of each wire is R/5. If we connect the pieces in parallel, we will get the net resistance as R/25. Therefore, the ratio will be 25.

Since the charge of an electron is 1.6×10−19C, 6.25 × 10 to the power 18 electrons taken together constitute (6.25 × 10 to the power 18 × 1.6 × 10−19 C) or 1 coulomb of charge.