Physics MCQs

Notes:
Alpha, beta and gamma radiations are emitted during the radioactive decay process. Alpha is positive particle with double positive charge, beta particle is an electron and hence negative charge, gamma radiation is neutral.

Notes:
Alpha-rays have high ionizing power but it is difficult for them to penetrate matter thoroughly. This is because alpha particles are likely to ionize the first thing they come into contact with; thus, they hold a small range of penetrating power. Beta rays have intermediate; while, Gamma Rays and X-Rays have maximum penetrating power.

Notes:
Water has its maximum density of 1g/cm3 at 4 degrees Celsius. When the temperature changes becoming either greater or less than 4 degrees, the density also changes with change in volume.

Notes:
Electric current is not a vector quantity. The other options – acceleration, force, and velocity – are all vector quantities that have both magnitude and direction. In contrast, electric current is a scalar quantity that has magnitude but no specific direction associated with it. Therefore, out of the choices provided, electric current is the one that is not a vector quantity.

Notes:
Velocity is a rate of the change of displacement with respect to time. so SI unit of velocity depend on the SI unit of displacement and time. SI unit of velocity is meter/second.

Notes:
Momentum depends upon the variables mass and velocity. In terms of an equation, the momentum of an object is equal to the mass of the object times the velocity of the object. The momentum is directly proportional to an object’s mass and directly proportional to the object’s velocity. If the velocity of a body is doubled its momentum also doubles.

Notes:
The unit of momentum is the product of the units of mass and velocity. In SI units, if the mass is in kilograms and the velocity is in meters per second then the momentum is in kilogram meters per second (kg m/s). The ampere is the SI base unit of electric current equal to one coulomb per second. The SI unit of energy is the joule. The kilogram per meter is a unit of measurement of linear density.

Notes:
Mass of the moon is 1/100 times and radius of moon is 1/4 times that of the earth .Therefore, the gravitational attraction on the moon is about one sixth of that on the earth. Hence, the weight of an object on the moon is 1/6th of the weight on the earth.

Notes:
If the relative humidity is 100 percent, water will not evaporate as the air is already saturated with moisture. When relative humidity approaches 100 percent, condensation can occur. The lower the relative humidity, the easier it is for moisture to evaporate. Therefore, people living in hot coastal areas suffen from heat stagnation.

Notes:
According to Pascal’s law of pressure, with the increasing depth, the pressure exerted by the water also increases. Hence, to resist the pressure which is exerted equally in all directions with the increasing depth, the thickness of walls increases.