Question Discussion & Solution

Concept:

ArithmeticException is an unchecked exception in Java. Usually, one would come across java. lang. ArithmeticException: Divide ( / ) by zero which occurs when an attempt is made to divide two numbers and the number in the denominator is zero

Code snippet:

int a = 0;

int b = 10/a      // divide by zero exception.

Additional Information 

• A null pointer exception is thrown when an application attempts to use null in a case where an object is required. These include: Calling the instance method of a null object. Accessing or modifying the field of a null object.
• Signals that a method has been invoked at an illegal or inappropriate time. In other words, the Java environment or Java application is not in an appropriate state for the requested operation
• The array index out of bounds error is a special case of the buffer overflow error. It occurs when the index used to address array items exceeds the allowed value. It's the area outside the array bounds which is being addressed, that's why this situation is considered a case of undefined behavior..

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 Ajmer.

Key Points​​

• Luni river:
  • The river originates at the confluence of two streams Saraswati and Sagarmati near Govindgarh of Ajmer district.
  • It flows in Ajmer, Nagaur, Pali, Jodhpur, Barmer. Jallore and drains in Rann of Kutch.
  • The water is fresh till Balotars of Barmer after that its water becomes salty.
  • The main tributaries of Luni joining from the left are the Lilri, the Guhiya, the Sukri, the Jawai, the Bandi (Hemawas), the Khari Bandi, the Sukri Bandi, and the Sagi.
  • Jojri is the only major tributary that joins the Luni river from the right.
  • The Dantiwada dam and the Sipu dam are constructed on the Luni river.
  • The main irrigation scheme in the Luni basin is Jawai dam, Jaswant Sagar dam, Hemavas, Sardar samand.

Additional Information

• Jaipur:
  • ​​Banganga, Bandi, Dhund, Morrel, Sabi are the river that flows in Jaipur.
  • Jaipur is also known as the 'Pink City', of India.
• Udaipur:
  • ​Banas, Ahar, Berach, Wakal, Gomti, Som, Jakham, Sabarmati, Sei are the river that flows in Udaipur.
• Nagaur:
  • ​​Luni, Mantha, Harsor are the rivers that flow in Nagaur.

The correct answer is Scatter plots.

Key Points

• Scatter plots
  • A correlation exists between two variables when one of them is related to the other in some way.
  • A scatterplot is the best place to start.
  • A scatterplot (or scatter diagram) is a graph of the paired (x, y) sample data with a horizontal x-axis and a vertical y-axis.
  • Each individual (x, y) pair is plotted as a single point.
  • Scatter plots are often used to find out if there's a relationship between variable X and Y. Hence, Option 2 is correct.
  • A scatterplot can identify several different types of relationships between two variables.
  • A relationship has no correlation when the points on a scatterplot do not show any pattern.
  • A relationship is non-linear when the points on a scatterplot follow a pattern but not a straight line.
  • A relationship is linear when the points on a scatterplot follow a somewhat straight line pattern. This is the relationship that we will examine.
• 

Additional Information

The correct answer is option 4) i.e. All of the above

CONCEPT:

• Magnetic field: The region around a magnet where its influence is experienced is called the magnetic field.
  • The visual representation of the magnetic field is called magnetic field lines.

​

• ​Properties of magnetic field lines:
  1. ​​The field lines start from the north pole and end at the south pole.
  2. The field lines are crowded where the magnetic field is the strongest.
  3. The field lines form continuous curves.
  4. The field lines do not intersect.

EXPLANATION:

• The magnetic field is strongest near the poles. Since magnetic field lines start and end at poles, they converge towards the region of strong magnetic force.
• Two magnetic field lines cannot intersect. If they did, at the point of intersection, the magnetic field will have two directions - which is not possible.
• The magnetic field lines have direction as they are represented as flowing, though no actual movement occurs. So, they do not move.

Therefore, all the given statements are true.