Biology disease and its virus for all competitive exam ( ssc,railways and other)

Assertion : If you burn a plant , its nitrogen component is given off as ammonia and other gases . Reason : Hydroponics does not allow plants to grow well if they are supplied with all the mineral nutrients they need.

A cube having all of its sides painted is cut by two horizontal, two vertical, and other two planes so as to form 27 cubes all having the same dimensions. Of these cubes, a cube is selected at random. The total number of cubes having at least one of its sides painted is

A cube having all of its sides painted is cut to be two horizontal, two vertical and other two planes, so as to form 27 cubes all having the same dimensions of these cubes. A cube is selected at random. If P_3 is the probability that the cube selected has none of its sides painted, then the value of 27P_3 is:

The period of moon's rotation around the earth is approx. 29 days. IF moon's mass were 2 fold its present value and all other things remain unchanged, the period of Moon's rotation would be nearly

A wire longates by 9 mm when a load of 10kg is suspended from it. What is the elongation when its radius is doubled, iff all other quantities are same as before ?

The members of a chess club took part in a round robin competition in which each player plays with other once. All members scored the same number of points, except four juniors whose total score ere 17.5. How many members were there in the club? Assume that for each win a player scores 1 point, 1/2 for a draw, and zero for losing.

The members of a chess club took part in a round robin competition in which each player plays with other once. All members scored the same number of points, except four juniors whose total score ere 17.5. How many members were there in the club? Assume that for each win a player scores 1 point, 1/2 for a draw, and zero for losing.

Which of the following statements are true for a rhombus? It has two pairs of parallel sides. It has two pairs of equal sides. It has only two pairs of equal sides. Two of its angles are at right angles. It diagonals bisect each other at right angles. Its diagonals are equal and perpendicular. It has all its sides of equal lengths. It is a parallelogram. It is a quadrilateral. It can be a square. It is a square.

Fill in the blanks: (i) The diameter of a circle is … times its radius (ii) The diameter of a circle is the … chord of the circle. (iii) The diameter of a circle pass through…. (iv) A chord of a circle is a line segment with its end points on the … (v) If we join any two points on a circle by a line segment, we obtain… (vi) A radius of a circle is a line segment with one end at …. and the other end at…. (vii) All radii of a circle are… (viii) The diameters of circle are… (ix) The total number of diameters of circle is… (x) Every point on a circle is…from its centre.. (xi) A chord of a circle contains exactly….points of the circle.. (xii) A diameter is the longest… (xiii) Concentric circles are circle having….

A ball of density d is dropped on to a horizontal solid surface. It bounces elastically from the surface and returns to its original position in a time t_1 . Next, the ball is released and it falls through the same height before striking the surface of a liquid of density of d_L (a) If dltd_L , obtain an expression (in terms of d, t_1 and d_L ) for the time t_2 the ball takes to come back to the position from which it was released. (b) Is the motion of the ball simple harmonic? (c) If d=d_L , how does the speed of the ball depend on its depth inside the liquid? Neglect all frictional and other dissipative forces. Assume the depth of the liquid to be large.