H C Verma Solutions for Chapter: Question Bank 1, Exercise 1: Question Bank

Below each item in the first column write the numbers of the appropriate items from the other two columns to match. One has been done for you. ($f=$focal length, $r =$ radius of curvature)

Two resistances R, and R2 are connected together. The resistance R2 can be varied from a very small value to a very large value. The equivalent resistance R varies with R2 as shown in the figure. In which way are the resistances joined—in series or in parallel?

Consider the two circuits shown in the figure. The cells, the material of the wires and the lengths of the wires are the same in the two cases. The only difference in the two circuits is the thickness of the wires. In which of the two will the ammeter give a larger reading?

What do you understand by a magnetic field? Does it have a direction? If yes, how will you find the direction of magnetic field at a point?

In houses how are devices such as fans and lights connected—in series or in parallel? Explain the advantages of the method of connection.

A wire of length $10 \mathrm{cm}$ and area of cross section $1\mathrm{mm}$ has a resistance of $5 \mathrm{\Omega }$. Find the resistivity of the material of the wire.

What values of resistances can you get by combining two resistances of values $8\Omega$ and $12\Omega$?

What values of resistances can you get by combining three $6\Omega$ resistances?