A gardener find some broad leaved dicot weed growing in the lawn. What can be done to get rid of these weeds efficiently.

Jasbeer saw some weeds growing in his field along with main crops. What is the process called in which these weeds are removed from the field?

What are weeds ?How can we control them ?

In a wheat field some broad - leaved weeds were found by a farmer .Which phytohormone can be used to eradicate them?

The Class X students of a secondary school in Krishinagar have been allotted a rectangular plot of land for their gardening activity. Sapling of Gulmohar are planted on the boundary at a distance of lm from each other. There is a triangular grassy lawn in the plot as shown in the Fig. The students are to sow seeds of flowering plants on the remaining area of the plot.:- Taking A as origin find the coordinates of the vertices of triangle .What will be the coordinates of the vertices of triangle PQR if C is the origin ? Also calculate the areas of the triangles in these cases. What do you observe ?

In an electric field the work done in bringing a 2 coulomb charge from infinity to a point a is 10 joules and in bringing the same charge to some another point B is 20 joule find the potential difference between two points A and B what would be the work done if the same charge is brought directly from A to B.

To find the sum of three numbers 14, 27 and 13. We can have two ways. We may add 27 and 13 to get 40 and then add 14 to get the sum 54. Thus This can be done for any three numbers. This property is known as the associativity of the addition of numbers. Express this property which we have already studied in the chapter on Whole Numbers, in a general way, by using variables a,b and c.

Read the given passage and answers following questions : The particles of colloidal solution possess electrical charge which is responsible for the stability of these solutions. The charge on colloidal particles arises because of selective adsorption of ions which are common with their own lattice. The presence of charge on colloidal particles can be determined with the help of phenomenon known as electrophoresis. However, when some electrolyte is added, the charge on the particles of, dispersed phase gets neutralized and precipitation takes place. This process is also called coagulation. The coagulation is given by Hardy Schulze rules. According to these rules the ions carrying the charge opposite to that of sol particles are effective and coagulating power of an electrolyte is directly proportional to the fourth power of the valency of the ion. Coagulation can also occur by mutual precipitation , by electrophoresis, by persistent dialysis or by heating or cooling. Answer the following questions : What happens to the charge of particles when electrolyte is added ?

The particles of colloidal solution possess electrical charge which is responsible for the stability of these solutions. The charge on colloidal particles arises because of selective adsorption of ions which are common with their own lattice. The presence of charge on colloidal particles can be determined with the help of phenomenon known as electrophoresis. However, when some electrolyte is added, the charge -on the particles of dispersed phase gets neutralized and precipitation takes place. This process is also called coagulation. The coagulation is given by Hardy Schulze rules. According to these rules the ions carrying the charge opposite to that of sol particles are effective and coagulating power of an electrolyte is directly propdrtional to the fourth power of the valency of the ion. Coagulation can also occur by mutual precipitation, by electrophoresis, by persistent dialysis or by heating or cooling. What happens to the charge of particles when electrolyte is added ?