Question Discussion & Solution

The correct answer is Nichrome.

Key Points

• Nichrome 
  • It is a metal alloy made up of around 20 percent of chromium and 80 percent nickel.
  • The key to the workings of an electrical heating element is the role of the nichrome in it.
  • Nichrome has fast emerged as the leading alloy to be used in terms of electrical heating elements.
  • For an electric iron heater element should have higher resistance, high melting point, and high specific heat.
  • An element should have high resistance so that it can hold its configuration in a high voltage current. It should have a high melting point such that it can sustain high temperatures.
  • Nichrome is used as a heating element in electric iron which is an alloy consisting 80% of Nickel and 20% of Chromium melting point of this element is 1400 degrees Celsius with high resistance which makes this element best for use as a heating element. Hence, Option 1 is correct.
  • The reason which makes the Nichrome best for heating elements is when it is heated in the air it develops an outer layer of chromium oxide which makes it stable in air and this chromium layer helps the element from oxidizing further during heating. 

Additional Information

• Copper
  • It is a chemical element with the symbol Cu and atomic number 29.
  • It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity.
  • A freshly exposed surface of pure copper has a pinkish-orange color.
• Silver
  • It is a chemical element with the symbol Ag and atomic number 47.
  • A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal.
• Lead
  • It is a chemical element with the symbol Pb and atomic number 82.
  • It is a heavy metal that is denser than most common materials.
  • Lead is soft and malleable, and also has a relatively low melting point.
  • When freshly cut, lead is silvery with a hint of blue it tarnishes to a dull gray color when exposed to air.

In this question we shows that Pen is used for Writing.

Similarly, Spoon is used for Eating.

But Gun comes under Weapon, Teacher teach in School and Eraser and Pencil is different things.

Option 1, 3 and 4 is not correct.

Hence, "Spoon : Eating" is the correct answer. 

The correct answer is Dungarpur.

• Dungarpur district of Rajasthan does not touch two States of India.

Key Points

• Dungarpur district is the third smallest district of Rajasthan.
  • It shares borders with Udaipur and Banswara districts.
  • The district consists of 5 tehsils Aspur, Dungarpur, Sagwara, Simalwara and Bchiwara.
  • Places of historic importance in Dungarpur are Juna Mahal, Udai Bilas Palace, Gaib Sagar Lake and Badal Mahal.

Additional Information

• Dholpur shares border with Bharatpur and Karauli district of Rajasthan
  • It also shares a border with Agra of Uttar Pradesh and Gwalior and Moreana of Madhya Pradesh.
• Bharatpur district touches the district of Alwar, Dholpur and Dausa of Rajasthan.
  • It also shares a border with the Mathura and Agra districts of Uttar Pradesh and Gurgaon district of Haryana.
• Hanumangarh shares its borders with Churu, Sri Ganganagar, Punjab and Haryana.

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.​

CONCEPT:

• The Correct Answer is Option (3) i.e. 1-d, 2-c, 3-b, 4-a.