Nursery to 10th Class Questions & Answers

A dicot leaf is the leaf of a dicotyledonous plant (a plant whose seed has two cotyledons). In simple words, many common plants around us, like hibiscus, mango, and rose, have dicot leaves. The easiest way to recognise it is to look at the veins. If the veins form a net-like pattern, it is usually a dicot leaf. Dicot Leaf with Examples How to Identify a Dicot Leaf Reticulate venation: The veins form a net (a network) instead of running parallel. Midrib is prominent: A main central vein is clearly visible, with many side veins branching out. Leaf is often broad: Many dicot leaves are wider, but shape can still vary a lot. Internal Structure (Useful for Biology Exams) Dorsiventral leaf: The upper and lower sides are not the same internally. Palisade mesophyll: Usually found towards the upper surface; it has more chloroplasts. Spongy mesophyll: Usually found towards the lower surface; it has more air spaces. Stomata: Often more on the lower surface in d...

Meaning: Centripetal force is the inward (center-seeking) net force that keeps an object moving in a circular path. No inward force = object goes straight along the tangent (Newton said "no curve without a cause"). Main Formula Fc = (m × v²) ÷ r What Each Symbol Means Fc = centripetal force (unit: Newton, N) m = mass (kg) v = speed along the circle (m/s) r = radius of the circular path (m) Why This Formula Works The centripetal acceleration in circular motion is: ac = v² ÷ r Using Newton's 2nd law F = m × a , we get: Fc = m × (v² ÷ r) So the final formula is: Fc = (m × v²) ÷ r Direction of Centripetal Force Centripetal force always acts toward the center of the circle. Velocity is tangential, but force is inward, so the object keeps turning instead of escaping like it has exam fear. Alternate Forms If you know angular speed (ω) instead of linear speed (v): v = ω × r ac = r × ω² Fc = m × r × ω² Quick Unit Check ...

Learning the electronic configuration of elements is the key to understanding how atoms behave, bond, and form compounds. From simple elements like Hydrogen to transition metals like Zinc, each has a unique pattern that explains its properties. The table below shows the electronic configuration, shell distribution, and valency of the first 30 elements in the periodic table. Following the table, we offer MCQs to help you quickly revise and test your knowledge in a fun and effective way. Electronic Configuration of Elements (1–30) Atomic Number Element (Symbol) Electronic Configuration (Subshell wise) Electronic Configuration (Shell wise) Valency 1 Hydrogen (H) 1s¹ 1 1 2 Helium (He) 1s² 2 0 3 Lithium (Li) 1s² 2s¹ 2, 1 1 4 Beryllium (Be) 1s² 2s² 2, 2 2 5 Boron (B) 1s² 2s² 2p¹ 2, 3 3 6 Carbon (C) 1s² 2s² 2p² 2, 4 4 7 Nitrogen (N) 1s² 2s² 2p³ 2, 5 3 8 Oxygen (O) 1s² 2s² 2p⁴ 2, 6 2 9 Fluorin...