Class 10 Science Chapter 11 MCQ

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

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.

In static electricity, the electric charges remain at rest or stationary, they do not move. The charge acquired by a glass rod rubbed with silk cloth and the charge acquired by an ebonite rod rubbed with woolen cloth are example of static electricity.

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].

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

In first case, Resistivity of the conductor, ƿ = RA¹/ l In second case, Resistivity of the conductor, ƿ = RA¹/ 2l Therefore, for same material, resistivity of the conductor will be same. So, on substituting the value of ƿ in Eq. (ii), we have RA/I = RA¹/2I = A¹ =2A

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 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.

We know that a thick wire has a greater area of cross section; whereas a thin wire has a smaller area of cross section. This means that a thick wire has less resistance and a thin wire has more resistance.

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.

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

In series circuit, the appliances do not get the same voltage as that of the power supply line because the voltage is shared by all the appliances. The appliances get less voltage and hence do not work properly. For example, all the bulbs connected in series do not get the same voltage of 220 volts of the power supply line. They get less voltage and hence glow less brightly.

The power in watts is found by multiplying the potential difference in volts by the current in amperes. We can write down the above formula for electric power in words as: Electric power = Potential difference x Current

Kilowatt-hour is the commercial unit of electrical energy.

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

A power rating of 100 W on the bulb means that it will consume electrical energy at the rate of 100 joules per second. If we know the power P and voltage V of an electrical appliance, then we can very easily find out the current I drawn by it. This can be done by using the formula: P = V x I

Electrical energy transferred per second, E = V x I x t = 6 V × 0.5 A × 1s = 3 J/s

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.