Human Eye and Colourful World — Science STD 10 — Question

Four identical wires each having resistance R are connected as shown in the figure. Equivalent resistance between A and B is:

The commercial unit of energy is:

1. Watt.
2. Watt-hour.
3. Kilowatt-hour.
4. Kilo-joule.

A 3-pin mains plug is fitted to the cable for a 1 kW electric kettle to be used on a 250 V a.c. supply. Which of the following statements is not correct?

The natural gas consists mainly of:

1. Methane.
2. Ethane.
3. Propane.
4. Butane.

How will crowding the wires of a solenoid, more closely together, will affect the strength of the field inside it?

A full length image of a distant tall building can definitely be seen by using:

1. A concave mirror.
2. A convex mirror.
3. A plane mirror.
4. Both concave as well as plane mirror.

Identify the incorrect statement: Magnetic field lines due to a circular coil is:

In which of the following, the image of an object placed at infinity will be highly diminished and point sized?

1. Concave mirror only.
2. Convex mirror only.
3. Convex lens only.
4. Concave mirror, convex mirror, concave lens and convex lens.

The stars appear higher in the sky than they actually are, due to:

Hans Christan Oersted, one of leading scientist of 19th century played a crucial role in understanding _________?