Hallwachs: zinc plate loses negative charge in UVहॉलवाक्स: पराबैंगनी प्रकाश में जिंक प्लेट का ऋण आवेश घटता हैHallwachs: zinc plate loses negative charge in UV

NCERT Sec 11.3.2 · Class 12 Physics · Chapter 11 · interactive diagram

Parts and what they mean

• Zinc plate (जिंक प्लेट) — Connected to the electroscope; here it is negatively charged.
• Gold-leaf electroscope (स्वर्णपत्र विद्युतदर्शी) — Its leaves spread apart when it is charged and fall when the charge is lost.
• Leaves diverged (पत्र फैले हुए) — Like charges on the two leaves repel: the plate is charged.
• Leaves collapse (पत्र सिकुड़ जाते हैं) — The negatively charged plate loses its charge in ultraviolet light, so the leaves fall.
• Ultraviolet light (पराबैंगनी प्रकाश) — UV light ejects negatively charged particles (electrons) from the zinc. An uncharged zinc plate even becomes positively charged.
• Ejected electrons (निकले हुए इलेक्ट्रॉन) — Hallwachs concluded that negatively charged particles are emitted; after 1897 they were known to be electrons.

Original diagram drawn by Simple Learning Hub, based on NCERT Sec 11.3.2. Report a mistake