Question Discussion & Solution

• For most computer languages, the name of the file that holds the source code to a program is immaterial
• However, in Java the name given to a source file is very important
• The Java compiler requires that a source file uses the .java filename extension
• Only file.java follow the properties in the given options
• In Java, a source file is officially called a compilation unit; It is a text file that contains one or more class definitions

Concepts:

Physical Properties of Metals and Non-metals

Explanation:

• Iodine is lustrous. This is an exception to the physical properties of non - metals. Iodine is non-metal and non - metals have dull appearance. 
• Sodium is metal. Metals are usually hard so this is also an exception. 
• Graphite conducts electricity. This is an exception as graphite is a form of carbon and it is non - metal. 
• Copper being metal is not an exception as it is metals and metals are good conductors of heat. 

So the correct option is 'Copper is a good conductor of heat.'

16 = 4²

100 = 10²

196 = 14²

216 = 6³

16, 100 and 196 are the perfect squares whereas 216 is a perfect cube.

The correct answer is binary.

Key Points

• Binary language is used by computers to process data.
• Binary code was invented by Gottfried Leibniz.
• A binary code is a two-symbol system that represents text, computer processor instructions, or any other data.
• The binary number system's "0" and "1" are frequently utilized as the two-symbol system.
• Each character, instruction, or other object is assigned a pattern of binary digits, commonly known as bits, by the binary code.

The correct answer is X-Ray.

• Electromagnetic (EM) radiation includes radiation via radio waves, microwaves, X-rays and gamma rays.

Key Points

• Electromagnetic (EM) radiation is a form of energy that is all around us and takes many forms.
• Electromagnetic (EM) radiation includes radiation via radio waves, microwaves, X-rays and gamma rays.
• Sunlight is also a form of EM energy.

​Additional Information

• ​EM radiation spans an includes a range of wavelengths and frequencies.
• This range is known as the electromagnetic spectrum.
• The EM spectrum is generally divided into seven regions:
  • Radio waves,
  • Microwaves,
  • Infrared (IR),
  • Visible light,
  • Ultraviolet (UV),
  • X-rays,
  • Gamma rays.

Important Points

• Radio waves have the longest wavelength.
• Gamma rays have the shortest wavelength.