CBSE GRADE 10 SCIENCE SET 1

Name the enzyme that acts on the protein-rich diet inside our stomach:

Which of the following is not a function of transpiration?

The growth of tendril in pea plant is due to which of the following?

Identify the hormone that regulates carbohydrate, protein and fat metabolism in the body:

From the following, identify the sexually transmitted diseases caused by bacteria. (i) Warts (ii) Gonorrhoea (iii) AIDS (iv) Syphilis. Choose the correct option:

Mendel crossed pea plants having yellow seeds (YY) with pea plants having green seeds (yy). Yellow seeds are obtained in F1 progeny which undergoes self-pollination to produce F2 progeny. Select the option showing the result of F2 progeny.

Which of the following options is not a step in the process of photosynthesis?

Assertion (A): Walls of the ventricles are thicker than those of the atria. Reason (R): Thick walls of the ventricles help in preventing the backflow of blood.

Assertion (A): In some reptiles, the temperature at which the fertilized eggs are kept determines whether the egg will develop into a male or a female. Reason (R): In human beings, the sex is determined genetically.

How is ozone layer formed in our atmosphere? State one important role of ozone in our atmosphere. What is responsible for its depletion?

During respiration, glucose is broken down into pyruvate. State the end products formed from it on further breakdown, in each of the following cases: (a) In yeast, in absence of oxygen. (b) Lack of oxygen in muscles. (c) In presence of oxygen in mitochondria.

Although most of the metals form basic oxides, which of the following metals forms an amphoteric oxide?

Which of the following metals forms an amphoteric oxide?

On heating ferrous sulphate crystals, one would get:

Butanal is a four-carbon compound with the functional group:

Which of the following are exothermic processes? I. The decomposition of vegetable matter into compost II. Dilution of an acid III. Evaporation of water IV. Sublimation of camphor

The soap molecule has a:

Which of the following statements is true for acids?

The property of carbon atoms by virtue of which they form bonds with other carbon atoms is called:

Assertion (A) : Burning of natural gas is an endothermic reaction. Reason (R) : Methane gas reacts with oxygen to produce CO2 and H2O.

Attempt either (a) or (b): (a) 2H6O reacts with acidified K2Cr2O7 and on oxidation gives an acidic compound. Presence of concentrated H2SO4 to give a sweet smelling substance. OR (b) Give reasons for the following: (i) Unsaturated hydrocarbons show addition reactions. (ii) Detergents are better cleansing agents than soaps. (iii) Carbon forms only covalent compounds.

(a) Identify the type of reaction taking place and mention why does the beaker become hot. (b) Write the balanced chemical equation.

Read the following passage and answer the questions: (a) What is the formula of POP (Plaster of Paris)? What is its chemical name? (b) Name the compound of sodium which is used for softening hard water. What is its chemical formula? (c) (i) (I) What is water of crystallization? (II) Write the preparation of bleaching powder. OR (c) (ii) (I) Name an indicator used by visually impaired children. (II) Give one use of bleaching powder.

Attempt either (a) or (b): (a) (i) Write the balanced chemical equation involved in the extraction of: (I) Hg from HgS (II) Zn from ZnCO3 (III) Na from NaCl (ii) Why does sodium chloride (I) not conduct electricity in solid state? (II) have very high melting point? OR (b) During extraction of metals, electrolytic refining is used to obtain pure metals. (i) Which material will be used as cathode and anode for refining of zinc metal by this process? (ii) Name the electrolyte used in this process. Where do we get pure zinc after passing electric current? (iii) How does zinc prevent rusting of iron? Also, name the process.

(b) During extraction of metals, electrolytic refining is used to obtain pure metals. (i) Which material will be used as cathode and anode for refining of zinc metal by this process ? (ii) Name the electrolyte used in this process. Where do we get pure zinc after passing electric current ? (iii) How does zinc prevent rusting of iron ? Also, name the process.

Pushkar was studying a light phenomenon and wrote down the following statements: (i) A concave mirror can be used as a shaving mirror. (ii) A convex lens always forms real, inverted images. (iii) The relationship between object distance (u), image distance (v) and focal length (f) of the lens is given by 1/f = 1/v - 1/u. Choose the option enlisting all the correct statements:

Pushkar was studying a light phenomenon and wrote down the following statements in that context: (i) A concave mirror can be used as a shaving mirror because it can form an enlarged, virtual image when the object is placed between the pole and focus. (ii) A convex lens always forms real, inverted images, regardless of the position of the object. (iii) The relationship between object distance (u), image distance (v) and focal length (f) of the lens is given by 1/f = 1/v - 1/u. Choose the option enlisting all the correct statements:

During a lab experiment, Bhavna uses a solenoid connected to a battery. She notes down the following facts: (i) The pattern of magnetic field lines inside the solenoid is similar to a bar magnet. (ii) The north pole and south pole of the current-carrying solenoid can be identified by applying the right hand thumb rule. (iii) A solenoid can be used to magnetise a piece of a soft iron, making it an electromagnet. Choose the option enlisting all the correct statements:

Assertion (A): For a medium of given refractive index, the value of the angle of refraction corresponding to an angle of incidence is not a constant. Reason (R): With change in angle of incidence, the value of angle of refraction changes. Hence, the ratio of sine of angle of incidence to sine of angle of refraction remains constant.

Attempt either (a) or (b): (a) Calculate the total resistance of the given circuit and find the total current flowing in it. OR (b) How would you join three resistors each of resistance 6 ohms, so that the equivalent resistance of the combination is (i) 9 ohms, and (ii) 4 ohms?

Draw the pattern of magnetic field produced by a current-carrying circular loop and name the factors on which the magnitude of the magnetic field due to a current-carrying circular coil depends.

State the reasons for myopia. With the help of a ray diagram, show the: (a) Image formation by myopic eye, and (b) Correction of myopic eye by using an appropriate lens.

What is meant by atmospheric refraction of light? Explain the following natural phenomenon by using the concept of atmospheric refraction: (a) Twinkling of stars (b) Flickering of objects seen through a turbulent stream of hot air

(a) When white light passes through a glass slab, it does not show dispersion, while it shows dispersion when it passes through a glass prism. Why ?

What is the use of fuse in domestic electric circuits? How is its role different from the role of a green coloured wire given in domestic electric circuits? What will happen if an electrician installs a fuse with higher-rated value than prescribed for a given electric circuit?

(b) Why do we get spectrum when white light passes through tiny water droplets present in air ?

Read the following passage and answer the questions that follow: Two students, A and B were performing an activity on refraction through a prism. Student A noted that the emergent light ray is parallel to the direction of incident ray, but shifted by some distance. Student B observed that when a light ray passes through a prism, it bends at an angle with respect to the direction of the incident ray in the prism, called angle of deviation. He also noted that the angle of deviation is different for different colours of light. (a) When white light passes through a glass slab, it does not show dispersion, while it shows dispersion when it passes through a glass prism. Why? (b) Why do we get spectrum when white light passes through tiny water droplets present in air? (c) (i) For a given pair of mediums, if we change the angle of incidence gradually, will it change the speed of light in that medium? Explain. OR (c) (ii) Calculate the speed of light in a given medium if angle of incidence in air is 60 and angle of refraction in the medium is 30. Given that speed of light in air is 3 x 10^8 m/s.

(c) (i) For a given pair of mediums, if we change the angle of incidence gradually, will it change the speed of light in that medium ? Explain.

(c) (ii) Calculate the speed of light in a given medium if angle of incidence in air is 60 and angle of refraction in the medium is 30. Given that speed of light in air is 3 x 10^8 m/s.

(a) A smart home uses energy monitoring system to track electricity usage of appliances. In a month of 30 days, the following devices are used : 1. An electric heater of 1500 W used for 4 hours daily. 2. A microwave oven rated at 1.5 kW used for 3 hours daily. (i) Define electric power and write its SI unit. (ii) Calculate the total energy consumed in joules and kWh in a whole month. (iii) Find out the total cost of electricity for running both appliances for a month of 30 days if the cost of 1 unit is 7.5

(b) (i) What is meant by electrical resistivity of a material ? (ii) A series electric circuit comprising a resistor made of a metallic wire has an ammeter which reads 300 mA. If the length of the wire is made three times, what will be the new reading in the ammeter ? (iii) Calculate the resistance of a 500 m long aluminium wire of cross-sectional area 1 x 10^-3 m^2 and resistivity 2.65 x 10^-8 Ohm-m.