Magnetism and Matter — Physics STD 12 Science — Question

An inductor coil of some resistance is connected to an AC source. Which of the following quantities have zero average value over a cycle?

In the given circuit, the voltmeter records 5 volts. The resistance of the voltmeter in ohms is

(a) 200

(b) 100

(c) 10

(d) 50

A charged particle moves along a circle under the action of possible constant electric and magnetic fields. Which of the following are possible?

An eye specialist prescribes spectacles having a combination of convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. The power of this lens combination in diopters is

(a) + 1.5

(b) – 1.5

(c) + 6.67

(d) – 6.67

Thirteen resistances each of resistance R ohm are connected in the circuit as shown in the figure below.  The effective resistance between A and B is

(a) 2R W

(b)

(c)

(d) R W

Identify the mismatched pair:

When a current in a circular loop is equivalently replaced by a magnetic dipole:

Assertion  : Amongst alpha, beta and gamma rays, a-particle has maximum penetrating power.

Reason      : The alpha particle is heavier than beta and gamma rays.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

The net resistance of an ammeter should be small to ensure that:

How much energy in kilowatt hour is consumed in operating ten 50 watt bulbs for 10 hours per day in a month (30 days).

(a) 1500

(b) 5,000

(c) 15

(d) 150