Which of the following are the properties of an electron?

1. Electron is a constituent of cathode ray
2. Electron is a negatively charged particle
3. The mass of the electron is equal to the mass of the proton
4. Electron is deflected by the electric field but not by magnetic field

Select the correct answer using the code given below:

• 1 and 2 only

• 1,2 and 3

• 3 and 4

• 1 and 4

The resistance of a wire of length l and area of crosssection a is x ohm. If the wire is stretched to double its length, its resistance would become:

• 2 x ohm

• 0.5 x ohm

• 4 x ohm

• 6 x ohm

Conservation of momentum in a collision between particles can be understood on the basis of:

• Newton's first law of motion

• Newton's second law of motion only

• Both Newton's second law of motion and Newton's third law of motion

• Conservation of energy

184.

Two forces, one of 3 newton and another of 4 newton are applied on a standard 1 kg body, placed on a horizontal and frictionless surface, simultaneously along the x-axis and the y-axis, respectively, as shown below:

The magnitude of the resultant acceleration is:

• 7 m/s²

• 1 m/s²

• 5 m/s²

• $\sqrt{7}$ m/s²

In SI unit of force 'Newton' (N) is given by (where m stands for metre and s stands for second):

• 1 N = 1 kg/ms²

• 1 N = 1 kgm/s²

• 1 N = 1 kg s²/m

• 1 N = 1 kg ms²

The acceleration due to gravity 'g' for objects on or near the surface of earth is related to the. universal gravitational constant 'G' as ('M' is the mass of the earth and 'R' is its radius):

• $\mathrm{G} = \mathrm{g}\frac{\mathrm{M}}{{\mathrm{R}}^2}$

• $\mathrm{g} = \mathrm{G}\frac{\mathrm{M}}{{\mathrm{R}}^2}$

• $\mathrm{M}=\frac{\mathrm{gG}}{{\mathrm{R}}^2}$

• $\mathrm{R}=\frac{\mathrm{gG}}{{\mathrm{M}}^2}$

The loudness of sound is related to:

• its frequency

• its amplitude

• its speed

• its pitch

X-rays are electromagnetic radiation whose wavelengths are of the order of:

• 1 metre

• 10^-1 metre

• 10^-5 metre

• 10^-10 metre

Which one of the following statements is correct?

• The image formed by a concave mirror for an object lying at infinity is at the principal focus, highly diminished, real and inverted

• A ray of light parallel to the principal axis after reflection from a concave mirror appears to diverge from the principal focus of the mirror

• The focal length of a spherical mirror is double of its radius of curvature

• A ray of light travelling from a rarer medium to a denser medium bends away from the normal

Examine the two statements carefully and select the answers to these items using the code given below:

Statement I: The acceleration due to gravity decreases with increase in height from the surface of the Earth.

Statement II: The acceleration due to gravity is inversely proportional to the square of the distance from the centre ofthe Earth.

• Both the statements are individually true and Statement II is the correct explanation of Statement I

• Both the statements are individually true but Statement II is not the correct explanation of Statement I

• Statement I is true but Statement II is false

• Statement I is false but Statement II is true