231.

The motion of a particle is given by a straight line in the graph given above drawn with displacement (x) and time (t). Which one among the following statements is correct?

• The velocity of the particle is uniform

• The velocity of the particle is non-uniform

• The speed is uniform and the particle is moving on a circular path

• The speed is non-uniform and the particle is moving on a straight line path

The human eye is like a camera and hence it contains a system of lens. The eye lens forms

• a straight or upright, real image of the object on the retina

• an inverted, virtual image of the object on the retina

• an inverted, real image of the object on the retina

• a straight or upright, real image of the object on the iris

A car is moving with a uniform speed. However its momentum is changing. Then the car

• may be on an elliptical path

• is moving on a straight path without acceleration

• is moving on a straight path with acceleration

• is moving without any acceleration

Ohm's law defines

• a resistance

• current only

• voltage only

• Both B and C

If d denotes the distance covered by a car in time t and $\overrightarrow{\mathrm{S}}$ denotes the displacement by the car during the same time, then:

• $\mathrm{d}\le \left|\overrightarrow{\mathrm{S}}\right|$

• $\mathrm{d}=\left|\overrightarrow{\mathrm{S}}\right| \mathrm{only}$

• $\mathrm{d}\ge \left|\overrightarrow{\mathrm{S}}\right|$

• $\mathrm{d}<\left|\overrightarrow{\mathrm{S}}\right|$

A current-carrying wire is known to produce magnetic lines of force around the conducting straight wire. The direction of the lines of force may be described by :

• left-hand thumb rule for up-current and right-hand thumb rule for down-current

• right-hand thumb rule for up-currentand left-hand thumb rule for down-current

• right-hand thumb rule for both up and down currents

• left-hand thumb rule for both up and down currents

If an object undergoes a uniform circular motion, then it's

• acceleration remains uniform

• velocity changes

• speed changes

• velocity remains uniform

A force F is applied on a body (which moves on a straight line) for a duration of 3 s. The momentum of the body changes from 10 g emfs to 40 g emfs. The magnitude of the force F is

• 10 dynes

• 10 newtons

• 120 dynes

• 12 dynes

Metal used to make wires for safety fuses must have

• very low resistivity and high melting point

• high resistivity and low melting point

• low resistivity and low melting point

• high resistivity and high melting point

A positively charged particle projected towards west is deflected towards north by a magnetic field. The direction of the magnetic field is

• towards south

• towards east

• in downward direction

• in upward direction