02:43

Molecular mass of Glucose C6H12O6

01:23

What is neutralisation reaction ?

01:20

State differences between acids and bases.

01:18

A bag contains lemon-flavoured candies only. Malini takes out one candy without looking into the bag

00:57

If P(E) = 0.05, what is the probability of ‘not E’?

01:26

Which of the following cannot be the probability of an event?(A) 2/3, (B) -1.5, (C) 15%, (D) 0.7

01:39

Light enters from air to glass having refractive index 1.50. What is the speed of light?

01:08

The probability of an event is greater than or equal to ___ and less than or equal to __________.

01:00

The sum of the probabilities of all the elementary events of an experiment is __________

01:08

Find the focal length of a convex mirror whose radius of curvature is 32 cm.

01:02

The probability of an event that is certain to happen is _________. Such an event is called ________

00:42

The radius of curvature of a spherical mirror is 20 cm. What is its focal length?

00:59

The probability of an event that cannot happen is __________. Such an event is called ________

01:20

Define the principal focus of a concave mirror.

01:03

Probability of an event E + Probability of the event ‘not E’ = ___________

04:31

The sum of the third and the seventh terms of an AP is 6 and their product is 8. Find the sum of fir

02:08

Find the sum of the odd numbers between 0 and 50

01:26

Find the sum of first 15 multiples of 8

02:14

Find the sum of first 40 positive integers divisible by 6

01:50

What is a balanced chemical equation ? Why should chemical equations be balanced ?

04:40

If the sum of the first n terms of an AP is 4n − n2, what is the first term (that is S1)? What is th

04:52

Show that a1, a2 … , an , … form an AP where an is defined as below(i) an = 3+4n(ii) an = 9−5n Also

04:31

If the sum of first 7 terms of an AP is 49 and that of 17 terms is 289, find the sum of first n term

02:05

Find the sum of first 51 terms of an AP whose second and third terms are 14 and 18 respectively

01:42

What happens when dilute hydrochloric acid is added to iron filings ? Tick the correct answer :

02:16

Find the sum of first 22 terms of an AP in which d = 7 and 22nd term is 149.

02:09

The first and the last term of an AP are 17 and 350 respectively. If the common difference is 9, how

02:43

Fe2O3 + 2Al → Al2O3 + 2FeThe above reaction is an example of a(a) combination reaction

02:15

The first term of an AP is 5, the last term is 45 and the sum is 400. Find the number of terms and

02:33

Which of the statements about the reaction below are incorrect ?2 PbO(s) + C(s) → 2Pb (s) + CO2(g)

02:26

The first term of an AP is 5, the last term is 45 and the sum is 400. Find the number of terms and d

02:01

Identify the substances that are oxidised and the substances which are reduced in the following rxn

05:53

How many terms of the AP. 9, 17, 25 … must be taken to give a sum of 636?

01:45

Two APs have the same common difference. The first term of one of these is –1 and that of the other

02:01

Give an example of a double displacement reaction

03:26

The sum of 4th and 8th terms of an A.P. is 24 and the sum of the 6th and 10th terms is 44. Find the

01:43

Why does the colour of copper sulphate solution change when an iron nail is dipped in it ?

01:50

Find the 20th term from the last term of the A.P. 3, 8, 13, …, 253.

02:20

Determine the A.P. whose third term is 16 and the 7th term exceeds the 5th term by 12

01:13

A solution of a substance ‘X’ is used for white washing.(i) Name the substance ‘X’ and write its .

02:50

for what value of n, are the nth terms of two APs 63,65,67 and 3,10,17.... equal?

02:11

How many multiples of 4 lie between 10 and 250?

03:02

How many three digit numbers are divisible by 7?

02:59

Which term of the A.P. 3, 15, 27, 39,.. will be 132 more than its 54th term?

03:06

Write a balanced chemical equation with state symbols for the following reactions :(i) Solutions ..

02:41

Write the balanced equation for the following chemical reactions.(i) Hydrogen + Chlorine → Hydrogen

02:34

Why should a magnesium ribbon be cleaned before burning in air ?

01:38

If 17th term of an A.P. exceeds its 10th term by 7. Find the common difference.

03:05

The mass per unit volume of a substance is called density.(density = mass/volume). class -9

05:04

(a) Tabulate the differences in the characteristics of states of matter. class-9

03:34

If the 3rd and the 9th terms of an A.P. are 4 and − 8 respectively. Which term of this A.P. is zero

02:46

An A.P. consists of 50 terms of which 3rd term is 12 and the last term is 106. Find the 29th term.

01:29

Question 4. What are the characteristics of the particles of matter? class-9

01:17

Which term of the A.P. 3, 8, 13, 18, … is 78?

01:28

A diver is able to cut through water in a swimming pool. Which property of matter does.. class 9

03:32

Find the 31st term of an A.P. whose 11th term is 38 and the 16th term is 73.

01:46

find 30th term of an AP 10,7,4..................

01:51

Give reasons for the following observation:The smell of hot sizzling food reaches you... Class-9

02:07

how to draw dot structure of co2

01:31

Question 1. Which of the following are matter?Chair, air, love, smell, hate, almonds, thought..