Electric Charges And Fields Important Questions Pdf Download BEST

[Vicky Greenwell]

<div>Question 40.</div><div></div><div>A small metal sphere carrying charge +Q is located at the centre of a spherical cavity in a large uncharged metallic spherical shell. Write the charges on the inner and outer surfaces of the shell. Write the expression for the electric field at the point P1 (Comptt. Delhi)</div><div></div><div></div><div></div><div>Answer:</div><div></div><div></div><div>Question 54.</div><div></div><div>An electric dipole of dipole moment \(\overrightarrow p \) is placed in a uniform electric field \(\overrightarrow E \)?. Obtain the expression for the torque \(\overrightarrow \tau \)experienced by the dipole. Identify two pairs of perpendicular vectors in the expression. (Comptt. Delhi 2015)</div><div></div><div>Answer:</div><div></div><div>(i)</div><div></div><div>(a) Torque on electric dipole. Consider an electric dipole consisting of two equal and opposite point charges separated by a small distance 2a having dipole moment</div><div></div><div></div><div></div><div>So net force on the dipole is zero</div><div></div><div>Since is uniform, hence the dipole does not undergo any translatory motion.</div><div></div><div></div><div></div><div></div><div></div><div>electric charges and fields important questions pdf download</div><div></div><div>Download: https://t.co/aGFX0mRa4w </div><div></div><div></div><div>Class 12 Physics Chapter 1 Electric Charges and Fields consists of questions on the linear charge density of an infinite line charge and many other questions regarding the electric field. In this chapter, students will be solving questions on how to calculate forces between two charged particles which are kept at a certain distance from each other. Students will be learning about the theory behind the charge appearing in materials due to rubbing against each other just like when we rub a glass rod with a silk cloth or a dry comb on our hair. There are many other interesting concepts in this chapter.</div><div></div><div></div><div>An electric field is a force field created by electric charges or changing electric currents. It influences the behaviour of charged particles within its area of influence, attracting or repelling them. The electric field is closely related to the magnetic field, as they are both parts of the electromagnetic field. This field is one of the four fundamental forces in nature. The electric field is often abbreviated as E-field. The electric field is a force field that is important in physics and has many practical applications in electrical technology. In atomic physics and chemistry, it is the attractive force that keeps the atomic nucleus and electrons together in atoms and is also responsible for the chemical bonding between atoms that leads to the formation of molecules.</div><div></div><div></div><div>1. A paisa coin is made up of AI-Mg alloy and weighs 0.75g. It has a square shape, and its diagonal measures 17 mm. It is electrically neutral and contains equal amounts of positive and negative charges. Treating the paisa coins made up of only Al, find the magnitude of the equal number of positive and negative charges. What conclusion do you draw from this magnitude?</div><div></div><div></div><div>Solution: In the given diagram, it shows that the electric field lines envelop the three-point charge A, B, and C.</div><div></div><div>(a) The charges C and A are positive as force lines emanate from them.</div><div></div><div></div><div>(b) The charge C possesses the largest magnitude since the maximum field lines are related to it.</div><div></div><div>(c) The correct answer is (i) near A.</div><div></div><div>Reason: No neutral point exists between a negative and a positive charge. A neutral point may occur between the two like charges. From the given diagram, it is known that a neutral point occurs between charges C and A. In the case of between two like charges, the neutral point is nearer to the charge with a relatively lesser magnitude. So, the electric field has zero value near charge A.</div><div></div><div></div><div></div><div></div><div></div><div></div><div>A more useful means of visually representing the vector nature of an electric field is through the use of electric field lines of force. Rather than draw countless vector arrows in the space surrounding a source charge, it is perhaps more useful to draw a pattern of several lines that extend between infinity and the source charge. These pattern of lines, sometimes referred to as electric field lines, point in the direction that a positive test charge would accelerate if placed upon the line. As such, the lines are directed away from positively charged source charges and toward negatively charged source charges. To communicate information about the direction of the field, each line must include an arrowhead that points in the appropriate direction. An electric field line pattern could include an infinite number of lines. Because drawing such large quantities of lines tends to decrease the readability of the patterns, the number of lines is usually limited. The presence of a few lines around a charge is typically sufficient to convey the nature of the electric field in the space surrounding the lines.</div><div></div><div></div><div>There are a variety of conventions and rules to drawing such patterns of electric field lines. The conventions are simply established in order that electric field line patterns communicate the greatest amount of information about the nature of the electric field surrounding a charged object. One common convention is to surround more charged objects by more lines. Objects with greater charge create stronger electric fields. By surrounding a highly charged object with more lines, one can communicate the strength of an electric field in the space surrounding a charged object by the line density. This convention is depicted in the diagram below.</div><div></div><div></div><div>A second rule for drawing electric field lines involves drawing the lines of force perpendicular to the surfaces of objects at the locations where the lines connect to object's surfaces. At the surface of both symmetrically shaped and irregularly shaped objects, there is never a component of electric force that is directed parallel to the surface. The electric force, and thus the electric field, is always directed perpendicular to the surface of an object. If there were ever any component of force parallel to the surface, then any excess charge residing upon the surface of a source charge would begin to accelerate. This would lead to the occurrence of an electric current within the object; this is never observed in static electricity. Once a line of force leaves the surface of an object, it will often alter its direction. This occurs when drawing electric field lines for configurations of two or more charges as discussed in the section below.</div><div></div><div></div><div>A final rule for drawing electric field lines involves the intersection of lines. Electric field lines should never cross. This is particularly important (and tempting to break) when drawing electric field lines for situations involving a configuration of charges (as in the section below). If electric field lines were ever allowed to cross each other at a given location, then you might be able to imagine the results. Electric field lines reveal information about the direction (and the strength) of an electric field within a region of space. If the lines cross each other at a given location, then there must be two distinctly different values of electric field with their own individual direction at that given location. This could never be the case. Every single location in space has its own electric field strength and direction associated with it. Consequently, the lines representing the field cannot cross each other at any given location in space.</div><div></div><div></div><div>In the examples above, we've seen electric field lines for the space surrounding single point charges. But what if a region of space contains more than one point charge? How can the electric field in the space surrounding a configuration of two or more charges be described by electric field lines? To answer this question, we will first return to our original method of drawing electric field vectors.</div><div></div><div></div><div>Suppose that there are two positive charges - charge A (QA) and charge B (QB) - in a given region of space. Each charge creates its own electric field. At any given location surrounding the charges, the strength of the electric field can be calculated using the expression kQ/d2. Since there are two charges, the kQ/d2 calculation would have to be performed twice at each location - once with kQA/dA2 and once with kQB/dB2 (dA is the distance from that location to the center of charge A and dB is the distance from that location to the center of charge B). The results of these calculations are illustrated in the diagram below with electric field vectors (EA and EB) drawn at a variety of locations. The strength of the field is represented by the length of the arrow and the direction of the field is represented by the direction of the arrow.</div><div></div><div></div><div>The diagram above shows that the magnitude and direction of the electric field at each location is simply the vector sum of the electric field vectors for each individual charge. If more locations are selected and the process of drawing EA, EB and Enet is repeated, then the electric field strength and direction at a multitude of locations will be known. (This is not done since it is a highly time intensive task.) Ultimately, the electric field lines surrounding the configuration of our two charges would begin to emerge. For the limited number of points selected in this location, the beginnings of the electric field line pattern can be seen. This is depicted in the diagram below. Note that for each location, the electric field vectors point tangent to the direction of the electric field lines at any given point.</div><div></div><div></div><div>The construction of electric field lines in this manner is a tedious and cumbersome task. The use of a field plotting computer software program or a lab procedure produces similar results in less time (and with more phun). Whatever the method used to determine the electric field line patterns for a configuration of charges, the general idea is that the pattern is the resultant of the patterns for the individual charges within the configuration. The electric field line patterns for other charge configurations are shown in the diagrams below.</div><div></div><div></div><div>In each of the above diagrams, the individual source charges in the configuration possess the same amount of charge. Having an identical quantity of charge, each source charge has an equal ability to alter the space surrounding it. Subsequently, the pattern is symmetrical in nature and the number of lines emanating from a source charge or extending towards a source charge is the same. This reinforces a principle discussed earlier that stated that the density of lines surrounding any given source charge is proportional to the quantity of charge on that source charge. If the quantity of charge on a source charge is not identical, the pattern will take on an asymmetric nature, as one of the source charges will have a greater ability to alter the electrical nature of the surrounding space. This is depicted in the electric field line patterns below.</div><div></div><div> 9738318194</div>