State which of the following are sets and which are not: A=A group of students of class-IX having heights from 4ft to 5ft,

Which of the following are sets? Justify your answer (i) The collection of all the months of a year begining with the letter "J". (ii) The collection of ten most talented writers of India. (iii) A team of eleven best cricket batsmen of the world. (iv) The collectionofall boys in your class. (v) The collection of all even integers.

The following distribution distribution given the state-wise, teacher-student ratio in higher secondary schools of India. Find the mode and mean of this data. Interpret the two measures.

There are 40 students in Class X of a school of whom 25 are girls and 15 are boys. The class teacher has to select one student as a class representative. She writes the name of each student on separate cards, the cards being identical. Then she puts cards in a box and stirs them thoroughly. She then draws one card from the box. What is the probability that the name written on the card is the name of (i) a girl? (ii) a boy?

A student records the following data for the magnitudes (B) of the magnetic field at axial points at different distances x from the centre of a circular coil of radius a carrying a current I. Verify (for any two) that these observations are in good agreement with the expected the oretical variation of B with x.

In a school, students thought of planting trees in and around the school to reduce air pollution. It was decided that the number of trees, that each section of each class will plant, will be the same as the class, in which they are studying, e.g., a section of Class I will plant 1 tree, a section of Class II will plant 2 trees and so on till Class XII. There are three sections of each class. How many trees will be planted by the students?

Go through the following statements:- (i). Primary spermatocytes undergo mitotic divisions to produce secondary spermatocytes (ii). Sperms released from the seminiferous tubules are fuly mature and motile (iii) The head of sperm possesses may mitochondria which produce energy for the movement of tail (iv) The human male ejaculates about 20-30 million sperms during a coitus which of these are correct?

The donations given to an orphanage home by the students of different classes of a secondary school are given below. Find the mean, median and mode of the data.

The Sun is a hot plasma (ionized matter) with its inner core at a temperature exceeding 10^(7)Kg , and its outer surface at a temperature of about 6000K. At these high temperatures , no substance remains in a solid or liquid phase. In what range do you expect the mass density of the Sun to be, in the range of densities of solids and liquids or gases ? Check if your guess is correct from the following data: mass of the Sun =2.0xx10^(30)Kg , radius of the Sun =7.0xx10^(8)m .

A survey conducted by a group of students as a part of their environment awareness programme, in which they collected the following data regarding the number of plants in 20 houses in a locality. Find the mean number of plants per house.