Class 10 Science

Why does the sun appear reddish early in the morning
Write the function of each of the following parts of human eye
Why do stars twinkle ? Explain
A student is unable to see clearly the words written on the black board
Describe in brief the structure and function of placenta
Draw excretory system in human beings and label the following organs of excretory system
Name the basic filtration unit present in the kidney
Define excretion
Write one structural difference between the composition of artery and veins
Write the function of valves present in between atria and ventricles
How is copper extracted from its sulphide ore
Write the steps involved in the extraction of pure metals in the middle of the activity series
What is a dam ? Why do we seek to build large dams
Students in a school listened to the news read in the morning assembly that the mountain of garbage in Delhi
Why are alloys commonly used in electrical heating devices
Why are metals good conductors of electricity whereas glass is a bad conductor of electricity
List the factors on which the resistance of a conductor in the shape of a wire depends
Write Joule’s law of heating
Show how would you join three resistors, each of resistance 9 Ω
State the laws of refraction of light. Explain the term absolute refractive index of a medium
Write one main difference between asexual and sexual mode of reproduction
Name the hormones secreted by the following endocrine glands
Write the name and structure of a saturated compound in which the carbon atoms
Why are most carbon compounds poor conductors of electricity
The pH of a salt used to make tasty and crispy pakoras is 14
2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube
Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants
If the image formed by a spherical mirror for all positions of the object placed in front of it is always erect and diminished
Write a and b in the given flow chart of neuron through which information travels as an electrical impulse
A compound ‘X’ on heating with excess conc. sulphuric acid at 443 K gives an unsaturated compound
Write the energy conversion that takes place in a hydropower plant
The current flowing through a resistor connected in a circuit and the potential difference
A student traces the path of a ray of light through a glass prism
List four precautions which a student should observe while preparing a temporary mount
After examining a prepared slide under the high power of a compound microscope
List in proper sequence four steps of obtaining germinating dicot seeds
What is observed when a pinch of sodium hydrogen carbonate is added to 2 mL of acetic acid
What would a student report nearly after 30 minutes of placing duly cleaned strips of aluminium
A teacher provided acetic acid, water, lemon juice, aqueous solution of sodium hydrogen carbonate
Calculate the equivalent resistance of the following network
Three resistors R1, R2 and R3 are connected in parallel and the combination is connected to a battery
Consider the given circuit and find the current flowing in the circuit and potential difference
How will you infer with the help of an experiment that the same current flows
How do nerve impulses travel in the body
Why is the use of iodised salt advisable
When do we consider a person to be myopic or hypermetropic
The sex of a newborn child is a matter of chance and none of the parents
What are homologous structures ? Give an example
What is hydrotropism ? Design an experiment to demonstrate this phenomenon
The electrons in the atoms of four elements A, B, C and D are distributed in three shells