Question Discussion & Solution

The correct answer is Element.

Key Points

• An electric room heater or an electric heater used for cooking contains a coil of wire.
• The coil of wire used in electric heaters is called a heating element.
• The heating coil of the electric room heater transfers the electric energy into heat energy.
• The elements become red hot and give out heat after connecting to the electric supply.
• The amount of heat produced in a wire depends on its material used, length, and thickness.
• The coil of the electric heater is made up of nichrome.
• Nichrome consists of 80% nickel, 20% chromium.

Additional Information

• The filament is usually made of very thin tungsten wire.
  • In an incandescent bulb, an electric current is passed through a metal filament.
• A cell is a single unit device that converts chemical energy into electric energy.
  • It produces electricity capable to run smaller appliances.
• A battery usually consists of a group of cells.

Mistake Points

• A filament is a fine resistance wire the purpose of which is to emit white light. 
• An element is a resistive wire the sole purpose of which is to produce heat.

The correct answer is Sodium carbonate.

Key Points

• A toothpaste is defined as a semi-solid material for removing naturally occurring deposits from teeth and is supposed to be used simultaneously with a toothbrush.
• Toothpaste generally contains the following components:
  • Water (20–40%)
  • Abrasives (50%) including aluminum hydroxide, calcium hydrogen phosphates, calcium carbonate, magnesium carbonate, silica, and hydroxyapatite.
  • Fluoride (usually 1450 ppm) mainly in the form of sodium fluoride.

The correct answer is A thin layer of silicon.

Key Points

• In computers, the chip is made up of a thin layer of silicon.
  • Computer chips are made of silicon, which is a semiconductor, and in order to make the most efficient use of it, chip manufacturers use sand that contains as much silicon as possible.
  • The mineral quartz is ideal for this purpose because its two main components are silicon and oxygen.
  • Silicon is used because it can be used as either an insulator (doesn't allow electricity to flow) or a semiconductor (allows a little flow of electricity).
  • This is important for making chips.
  • It is very, very cheap.
• Hence, option 2 is correct. 

Additional Information

• Silicon is used for electronic devices because it is an element with very special properties.
  • One of its most important properties is that it is a semiconductor.
  • This means that it conducts electricity under some conditions and acts as an insulator under others.
  • It is even the most common element in the Earth's crust. 
• Lady Ada Lovelace invented looping in computer programming​.
  • Lady Ada Lovelace wrote a complete plan describing the algorithm needed to calculate the Bernoulli numbers using two loops, demonstrating the bifurcation capabilities of the analytical machine, describing how to perform trigonometric operations that made use of variables.

The correct answer is OMR.

Important Points

• Optical mark recognition
  • It is the input device used to scan a marked answer book of a multiple choice question paper.
  • An optical answer sheet or bubble sheet is a special type of form used in multiple-choice question examinations. 
  • Optical mark recognition is used to detect answers.

Additional Information

• OCR
  • ​OCR (Optical Character Recognition) recognizes all the characters from the paper document.
  • It collects and stores them into an editable document.
• ​MICR
  • ​The term magnetic ink character recognition (MICR) refers to the line of numbers that appears at the bottom of a check.
  • The MICR line is a group of three numbers, which are the check number, account number, and bank routing number.
• Card reader
  • A card reader is a data input device that reads data from a card-shaped storage medium.

Copper is a type of metal similarly, rupee is a currency of India.