10 self study question with answer--24

Question 1

The SI unit of density is_______.

  kg m^-3

  g cm^-3

  kg wt cm^-2

  none of these

It's 'kg m^-3 '
The density of a substance is its mass per unit volume. The SI unit of densityis Kg m^-3.

Question 2

The wire having a green plastic covering is a _____?

  Line wire

  Neutral wire

  Earth wire

  None of these

It's 'Earth wire '
Earth wire is a crucial part of the home electrical system and is designed to protect against electric shock.

Question 3

Fat can be separated from milk in a cream separator because of __________?

  cohesive force

  gravitational force

  centripetal force

  centrifugal force

It's 'centrifugal force '
The centrifugal separator was invented in 1897. By the turn of the century it had altered the dairy industry by making centralized dairy processingpossible for the first time. It also allowed removal of cream and recovery ofthe skim milk in a fresh state.

Question 4

A dynamo converts______.

  Mechanical energy into sound energy

  Mechanical energy into electrical energy

  Electrical energy into mechanical energy

  None of these

It's 'Mechanical energy into electrical energy '
The dynamo by attaching it in between the two tires, converts the mechanical energy into electrical energy and by connecting the wires going out of thedynamo to light it glows without any flaw.

Question 5

Which are the primary Colours?

  Yellow, Green, Blue

  Red, Magenta, Blue

  Red, Green, White

  Red, Green, Blue

It's 'Red, Green, Blue '
Red, Green, Blue are primary colours. All the colours can be produced by them by mixing in different proportions.

Question 6

Longitudinal waves and Transverse waves are types of _______.

  Mechanical waves

  Non-Mechanical waves

  Both of above

  None of Above

It's 'Mechanical waves '
Mechanical Waves are waves which propagate through a material medium at a wave speed which depends on the elastic and inertial properties of that medium. There are two basic types of wave motion for mechanical waves:longitudinal waves and transverse waves.

Question 7

A typical example of a semiconductor is _______?

  platinum

  germanium

  quartz

  mica

It's 'germanium '
Germaniumis a chemical element with symbol Γε and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, Purifiedgermanium is a semiconductor.

Question 8

Which of the following is used in oven?

  X-rays

  UV-rays

  Microwaves

  Radio waves

It's 'Microwaves '
An oven is a thermally insulated chamber used for the heating, baking ordrying of a substance and most commonly used for cooking.

Question 9

Dentists use a _____________ to focus light on the tooth of a patient.

  concave mirror

  convex mirror

  plane mirror

  cylindrical mirror

It's 'concave mirror '
Concave mirrors are used by dentists because at a short range they produce magnified, upright images. It is useful to have a magnified image of a toothwhen you're looking for or repairing cavities, cracks, other abnormalities.

Question 10

An athlete can take a longer jump if he comes running from a distance as compared to that when he jumps suddenly. Identify the type of inertia?

  Inertia of rest

  Inertia of motion

  Inertia of direction

  Inertia of position

It's 'Inertia of motion '
Inertiais the resistance of any physical object to any change in its state of motion, including changes to its speed and direction. It is the tendency of objects to keep moving in a straight line at constant velocity.