Diagrams carry real marks. ISC examiners expect correct labels with arrows. Practise drawing these from memory — not from the textbook.
ISC Class 12 Important Diagrams
Must-draw diagrams for ISC Class 12 Physics and Biology — what to label, marks allocated, and how often each appears in the CISCE board exam.
Physics
Parallel plate capacitor with dielectric
Electrostatics
Must label: Plates, dielectric slab, charge distribution, field lines
Moving coil galvanometer — internal structure
Magnetic Effects of Current and Magnetism
Must label: Coil, permanent magnet, cylindrical core, spring, pointer
AC generator — diagram and working
Electromagnetic Induction and Alternating Currents
Must label: Armature coil, field magnets, slip rings, brushes, external circuit
Transformer — construction diagram
Electromagnetic Induction and Alternating Currents
Must label: Primary and secondary coils, iron core, Np, Ns turns
Compound microscope — ray diagram
Optics — Ray Optics
Must label: Objective lens, eyepiece, object, intermediate image, final image, 2F₀, F₀, Fe
Astronomical telescope — normal adjustment
Optics — Ray Optics
Must label: Objective, eyepiece, parallel rays, image at infinity, focal lengths
Young's double slit experiment setup
Optics — Wave Optics
Must label: S₁, S₂ slits, screen, path difference, central maximum, bright/dark fringes
Energy band diagrams — conductor, semiconductor, insulator
Electronic Devices
Must label: Valence band, conduction band, forbidden gap (Eg), Fermi level
p-n junction diode in forward bias
Electronic Devices
Must label: p-type, n-type, depletion region (narrowed), battery polarity
Biology
V.S. of a mature anther
Sexual Reproduction in Flowering Plants
Must label: Epidermis, endothecium, tapetum, middle layers, pollen grains, connective tissue, vascular bundle
Structure of ovule (anatropous)
Sexual Reproduction in Flowering Plants
Must label: Funicle, chalaza, integuments, micropyle, nucellus, embryo sac, hilum
L.S. of a seed — dicot (bean)
Sexual Reproduction in Flowering Plants
Must label: Testa, tegmen, cotyledons, plumule, radicle, hilum, micropyle
Structure of the human male reproductive system
Human Reproduction
Must label: Testes, epididymis, vas deferens, seminal vesicle, prostate gland, urethra, penis
Structure of the human female reproductive system
Human Reproduction
Must label: Ovaries, fallopian tubes, uterus, cervix, vagina, fimbriae
Diagrammatic representation of DNA double helix
Molecular Basis of Inheritance
Must label: Sugar-phosphate backbone, hydrogen bonds, base pairs (A-T, G-C), 5' and 3' ends
Diagrammatic representation of transcription in eukaryotes
Molecular Basis of Inheritance
Must label: Template strand, coding strand, RNA polymerase, mRNA, direction of synthesis
Structure of an antibody molecule
Human Health and Disease
Must label: Heavy chains, light chains, variable region, constant region, antigen-binding sites, disulfide bonds
T-DNA integration into plant chromosome (Agrobacterium-mediated)
Biotechnology
Must label: Ti plasmid, T-DNA, disarmed vector, plant chromosome, integration site
Pyramids of energy in an ecosystem
Ecosystem
Must label: Producers, primary consumers, secondary consumers, tertiary consumers, energy values