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Most students open the CBSE sample paper, attempt it once and put it away. You can get much more from it. The 2026-27 Class 10 Science sample question paper shows exactly how the board builds the paper: which subject sits where, how many marks each type of question carries, and where the internal choices are. This post takes it apart question type by question type, works three answers with the official marking scheme, and ends with a time plan.
How is the 2026-27 science paper laid out?
The sample paper's instructions say it has 39 questions in three sections: Section A is Biology, Section B is Chemistry and Section C is Physics. All questions are compulsory, with internal choice in some. Every page carries the note that there is no change in the question paper design and assessment pattern for 2026-27. The paper is 80 marks in 3 hours.
Adding the marks printed against each question gives this picture:
Section A, Biology (Q1 to Q16): 30 marks. Nine 1-mark questions (including two assertion-reason items), three 2-mark, two 3-mark, one 4-mark and one 5-mark question.
Section B, Chemistry (Q17 to Q29): 25 marks. Eight 1-mark questions (including one assertion-reason item), one 2-mark, two 3-mark, one 4-mark and one 5-mark question.
Section C, Physics (Q30 to Q39): 25 marks. Three 1-mark questions (including one assertion-reason item), two 2-mark, three 3-mark, one 4-mark and one 5-mark question.
That totals 20 one-mark questions, 6 two-mark, 7 three-mark, 3 four-mark and 3 five-mark questions. The split matches the CBSE 2026-27 science curriculum, where World of Living (25) and Natural Resources (5) make up 30 marks, Chemical Substances is 25, and Natural Phenomena (12) plus Effects of Current (13) is 25. Our six-week Class 10 science revision plan uses the same unit marks to plan revision.
What does each type of question ask you to do?
The curriculum's question paper design puts about 50% of marks on knowledge and understanding, 30% on application, and 20% on analysing, evaluating and creating, with internal choice in about 33% of the paper.
In the sample paper, that looks like this:
1-mark multiple choice questions are often small experiments, not definitions. Q2 asks which of four set-ups kept in sunlight would turn lime water cloudiest.
Assertion-reason questions have two parts to check. In Q9, the assertion says 1% of energy passes to the next trophic level; it is the reason, with 10%, that matches the textbook. Judge each statement on its own first, then ask whether the reason explains the assertion.
4-mark questions come with sub-parts and a choice inside. Q15 is a Mendelian cross; Q38 is a solenoid door lock in a school.
5-mark questions have a full A-or-B choice. Read both options before you start; pick the one where you can write every part.
The sample paper also prints separate versions of diagram questions for visually impaired candidates. These are useful extra practice for everyone, because they state in words what the figure shows.
How do the marks split inside an answer?
The marking scheme shows where each mark goes. Three examples:
Q35, a concave lens (3 marks). An object 24 cm in front of a lens gives an image one-third its size; find the lens type, image distance and focal length. A concave lens forms a virtual, erect, smaller image, so m = +1/3. With u = −24 cm, v = m × u = (1/3) × (−24) = −8 cm. Then 1/f = 1/v − 1/u = −1/8 + 1/24 = −3/24 + 1/24 = −2/24, so f = −12 cm. The scheme gives a mark for each part. Common mistake: dropping the sign of u, which gives a positive focal length and the wrong lens.
Q37, the version for visually impaired candidates (3 marks). A 15 V battery with 2 Ω, 3 Ω and 5 Ω in series. Total resistance R = 2 + 3 + 5 = 10 Ω. Current I = V/R = 15/10 = 1.5 A. Voltage across the 3 Ω resistor = 1.5 × 3 = 4.5 V. Check: 3 V + 4.5 V + 7.5 V = 15 V. For more circuit practice, see our guide to Class 10 electricity.
Q14, a food chain (part A). If the fourth trophic level gets 10 kJ, the producer level had 10 kJ × 10 × 10 × 10 = 10,000 kJ, because only about 10% passes up each step. The scheme's answer is 10000 kJ. Common mistake: multiplying by 10 four times instead of three. Count the steps, not the levels.
How should you spend the 3 hours?
At 80 marks in 180 minutes, you have about 2 minutes per mark. One plan, which you can adjust after a timed practice paper:
First 5 minutes: read the whole paper, and mark your choices in every A-or-B question.
Biology, about 60 minutes for 30 marks.
Chemistry, about 50 minutes for 25 marks.
Physics, about 50 minutes for 25 marks, with numericals written step by step and units on every line.
Last 15 minutes: check signs in lens questions, units, and that every part of every question has an answer.
You do not have to go in section order. If physics numericals are your strength, start there to bank marks, but keep to the time for each section.
A two-week practice routine
Days 1 to 3: do one section of the sample paper a day under time, then mark it with the official scheme.
Days 4 to 7: list every mark you lost by type: wrong concept, missing step, sign or unit, or misread question.
Days 8 to 12: for your two most common loss types, do ten targeted questions a day. Ray diagrams and lens sums need daily practice; our post on light, reflection and refraction has more.
Days 13 and 14: take the full paper again in 3 hours, without looking at your first attempt.
If a numerical keeps going wrong at the same step, the Fermi Problem Library has worked problems with a step-by-step solver that explains the reasoning rather than printing an answer.
Download the sample paper and marking scheme today and time yourself on Section C first.
