A circular coil of single turn has a resistance of 20 Ω. Which one of the following is the correct value for the resistance between the ends of any diameter of the coil?

• 5 Ω

• 10 Ω

• 20 Ω

• 40 Ω

In a solenoid, the current flowing through the wire is l and number of turns per unit length is n. This gives a magnetic field B inside the solenoid. If numbers of turn per unit length is increased to 2n, what will be the value of magnetic field in the solenoid?

• B

• 2B

• B/2

• B/4

Which one of the following statements is correct about the magnification of an optical microscope?

• Magnification increases with the increase in focal length of eyepiece

• Magnification increases with the increase in focal length of objective

• Magnification does not depend upon the focal length of eyepiece

• Magnification decreases with the increase in focal length of eyepiece

The radii of curvature of the faces of a double convex lens are 10 cm and 20 cm. The refractive index of the glass is 1.5. What is the power of this lens (in units of dioptre)?

• +7.5 D

• -7.5 D

• +2.5 D

• +5.0 D

The time period of a simple pendulum made using a thin copper wire of length L is T. Suppose the temperature of the room in which this simple pendulum is placed increases by 30°C, what will be the effect on the time period of the pendulum?

• T will increase slightly

• T will remain the same

• T will decrease slightly

• T will become more than 2 times

Which one of the following physical quantity has the same unit as that of pressure?

• Angular momentum

• Stress

• Strain

• Work

Which one of the following statements is correct with regard to the material of electrical insulators?

• They contain no electrons

• Electrons do not flow easily through them

• They are crystals

• They have more number of electrons than the protons on their surface

Which one of the following physical quantities does NOT affect the resistance of a cylindrical resistor?

• The current through it

• Its length

• The resistivity of the material used in the resistor

• The area of cross-section of the cylinder

109.

Suppose a rod is given a negative charge by rubbing it with wool. Which one of the following statements is correct in this case?

• The positive charges are transferred from rod to wool

• The positive charges are transferred from wool to rod

• The negative charges are transferred from rod to wool

• The negative charges are transferred from wool to rod

Which one of the following is the correct relation between frequency ƒ and angular frequency ω?

• ƒ = πω

• ω = 2πƒ

• ƒ = 2ω/π

• ƒ = 2πω