Ask a Teacher

Search

CBSE->Std 10 Questions

Total Questions 2595
If cars are only at 50% efficient in energy use, doesn't that break the law of conservation of energy? Explain
1. What is CFL? 2. How does it work? 3. What is the advantage so using CFL over incandescent bulb?
a student takes about 2 ml ethanoic acid in a dry test tube and adds a pinch of sodium hydrogen carbonate to it.he reports the following observations:a)immediately a colorless and odourless gas evolves with a brisk effervescence.b)gas turns lime water milky when passed through it.c)gas burns with an explosion .d)gas extinguishes the burning splinter that is brought near it. which are the three correct observations?
we need 20% aqueous solution of sodium hydroxide for the study of saponification reaction.when we open the lid of the bottle containing solid sodium hydroxide we observe it in which form? a)colorless transparent beads b)small white beads c)white pellets/flakes d)fine white powder
while studying saponification reaction,a student measures the temperature of the reaction mixture and also find its nature using blue/red litmus paper.on the basis of his observations the correct conclusions would be: a)reaction is exothermic and mixture is acidic b)reaction is endothermic and mixture is acidic c)reaction is endothermic and mixture is basic d)reaction is exothermic and reaction is basic. which type of NaOH is used for Saponification?
what is the correct sequence of the steps to observe the slide of amoeba under the microscope? a)adjust the diaphragm and the mirror of the microscope so that sufficient light may enter to illuminate the slide. b)fix the slide on the stage carefully. c)adjust the microscope to high power and focus. d)adjust the microscope to low power and focus.
What is the main difference between sperms and eggs of humans? write the importance of this difference.
The diameter of a sphere is decreased by 25%. By what percentage will its CSA be decreased?
water in a canal, 6m wide and 1.5m deep, is flowing at a speed of 4km/h. how much area will it irrigate in 10 minutes, if 8cm of standing water is needed for irrigation.
the largest possible sphere is carved out of a wooden solid cube of side 7 cm. find the volume of the wood left.
two different dice are tossed together. find the probability the number on each die is even.
two circles touch each other externally at P. AB is a common tangent to the circles touching them at A & B. the value of angle APB is
in a family of 3 children, the probability of having at least one boy is
The probability that a number selected at random from the numbers 1,2,3,.....,15 is a multiple of 4.
150 spherical marbles ,each of diameter 1.4 cm ,are dropped in a cylindrical vessel of diameter 7 cm containing some water ,which are completely immersed in water.find the rise in the level of water in the vessel.
how to calculate the average atomic mass of bromine atom Given; 2 isotopes 79/35 Br[49.7] and 81/35 Br[50.3]
Explain the functions of vagina and labia?
who is the father of modern mathematics?
a right circular cone is divided by a plane parallel to its base into 2 equal volumes .in what ratio will the plane divide the axis of the cone?
Two men on either side of a cliff, 60m high, observe the angles of elevation of the top of the cliff to be 45 degree & 60 degree respectively. find the distance between two men.