Question Discussion & Solution

Concept-

• Roots are the underground structures that help in the absorption of water and minerals, provide a proper anchorage to the plant parts, storage of reserve food material (Carrot, Radish), and synthesis of PGR (plant growth regulators).
• Sometimes roots get modified to perform different functions like Storage of food, respiration, climbing, etc.
• These types of roots are called modified roots.

Explanation-

• The Coralloid roots are the specialized roots found in cycas, these roots exhibit a symbiotic relationship between the cyanobacteria and cycas where the cyanobacteria fix the nitrogen and in return, the cycas provide a stable environment to live.
• Cycas, a genus of 105 species of palmlike tropical and subtropical ornamental cycads (family Cycadaceae), among them trees 12 meters (40 feet) or more in height. 
• Their leaves are dark green and circinate (uncoiling as fern leaves do), differing from those of other members of the family in having a midrib but no lateral veins. 
• The seeds are borne along the margins of modified leaves, which are arranged in a whorl at the top of the trunk, rather than in compact cones. 

Thereby coralloid roots are found in cycas.

Additional Information

• Lycopodiopsida
  • It is a class of herbaceous vascular plants known as lycopods, lycophytes.
  • Members of the class are called clubmosses, firmosses, and quillworts.
• Pine
  • A pine is any conifer in the genus Pinus of the family Pinaceae. Pinus is the sole genus in the subfamily Pinoideae.
• Dryopteris
  • It is commonly called the wood ferns, male ferns, or buckler ferns is a fern genus in the family Dryopteridaceae.​

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.

A constructor is a member function of a class that initializes objects of a class. In C++, Constructor is automatically called when an object (instance of a class) creates. It is a special member function of the class.

Syntax

class_name(parameter1, parameter2, ...)

{

    // constructor Definition

}

Default Constructor

It is the constructor that doesn’t take any argument. It has no parameters.

Parameterized Constructors

It is possible to pass arguments to constructors. Typically, these arguments help initialize an object when it is created. 

Copy Constructor

A copy constructor is a member function that initializes an object using another object of the same class.

Here the pattern is,

8 + 1² = 8 + 1 = 9

9 + 2² = 9 + 4 = 13

13 + 3² = 13 + 9 = 22 ¹ 27

22 + 4² = 22 + 16 = 38

Hence, 27 is the odd one out

Concept

The javac command in Java compiles a program from a command prompt.

It reads a Java source program from a text file and creates a compiled Java class file.

Syntax

javac filename [options]

For example, to compile a program named Abc.java, use this command:

javac Abc.java