Question Discussion & Solution

CONCEPT:

Electric Charge: It is a physical property of a matter that experiences a force when placed in an electromagnetic field.

• Electric charges create electric fields.

• Two types of charges are found – 1.) Positive charge. 2.) Negative charge
• Force experienced when charge placed in the electromagnetic field is \({{F}^{\to }}=q\times {{E}^{\to }}\) where q = charge of the body (in coulomb). \({{E}^{\to }}\) = intensity of the electric field.
• SI unit of charge is Coulomb and the symbol is C. One coulomb is equal to the charge on 6.241 x 10¹⁸ protons.

Inductor: It is a passive electric component that stores energy in the form of magnetic field lines. It is a simple loop of wire.

• The inductance of the inductor could be measured by equation L = Φ / I where ϕ is magnetic flux and I is a current flowing through it.
• SI unit of inductance is Henry.
• Energy stored in Inductor U = ½ (LI²).

Capacitor: It is a device consisting of two conducting "plates" separated by an insulating material (dielectric). It stores energy in the form of an electric field with the help of an electric charge.

• The capacitance of a capacitor is measured by equation C = q /Δ v where q is charge and ∆ V is a potential difference.
• SI Unit of capacitance is Farad.
• Energy stored in Capacitor U = ½ (CV²)

Resistance: It is a measure of how the device reduces the flow of electric current, basically it opposes the flow of charges.

• Further, it states the ratio of the applied voltage to electric current flows through it.
• R = V/I [R is resistance, V is the potential difference and I is electric current].
• Also, R = ρ × (L/A) [where ρ is specific resistance of the material, l is the length of conductor and A is the cross-sectional area of the conductor].
• The unit of resistance is volt/ampere or ohm (Ω).
• It does not store energy.

Transformer: It is an electrical device that converts A/C current from one voltage to another.

EXPLANATION:

• A capacitor stores energy in the form of electrical charges and fields.
• Here, C_o = Capacitance, V = voltage, A = area of the plates, d = distance between them.

\(\Rightarrow {{C}_{o}}=\frac{{{Q}_{o}}}{V}=\frac{{{\epsilon }_{o}}A}{d}\)

Important Points

• Remember Electric field lines are stored in capacitor & magnetic field lines are stored in Inductor.

The correct answer is Femur.

Key Points

• The largest bone in the human body is the femur, the thighbone.
• It is the largest, longest, and strongest bone in the human body.
• The femur runs from the keen to the hip.
• The Femur or thigh bone is the largest and heaviest bone in the human body.
• At the proximal end of the Femur, there is a rounded prominence which is called the Head of the Femur.
• The femur runs from the keen to the hip.
• It carries all the upper body weight.
• The other parts of the leg are the tibia, femur, fibula, and keep cap also known as patella.

Additional Information

• The human skeleton is made up of 206 bones, including bones of the
  • Skull:  including the jaw bone (mandible, maxilla)
  • Spine: cervical, thoracic and lumbar vertebrae, sacrum and tailbone (coccyx)
  • Chest: ribs and breastbone (sternum)
  • Arms: the shoulder blade (scapula), collar bone (clavicle), radius, humerus and ulna
  • Hands: wrist bones (carpals), metacarpals and phalanges
  • Pelvis: hip bones
  • Legs: the thigh bone (femur), the kneecap (patella), shin bone (tibia) and fibula
  • Feet: tarsals, metatarsals, and phalanges.

The correct answer is Atomic Energy.

Key Points

• A biomass energy source is one that is derived from organic matter.
• The source of atomic energy is radioactive metals which are of non-organic nature and thus cannot be classified as a biomass energy source.

The pattern followed is:

Hence, the correct answer is "72".

The correct answer is Light Pen.

Key Points 

• Light Pen -
  • It is an input device of the computer which serves to give commands to the computer.
  • It is also called an electronic pen.
  • It looks like an ordinary pen.
  • It is used as a mouse.

Additional Information 

• A wave of light emerges from the tip of this pen.
• With this point, the icon made on the screen is touched and clicked.
• This work is done in the same way that we click by moving the mouse pointer on the screen.
• The tip of the light pen acts in a way like the Enter / Ok button.​