15 Questions
What was the experimental setup used to discover electrons?
Gas-discharge tube experiment
What is the direction of cathode rays in a gas-discharge tube?
From the negative electrode to the positive electrode
What happens when cathode rays strike a thin metal foil?
It gets heated up
What is a characteristic of cathode rays in a gas-discharge tube?
They have a fixed charge-to-mass ratio regardless of the gas used
What happens when cathode rays strike a zinc sulphide screen?
It produces a green glow
What is a property of cathode rays in a gas-discharge tube?
They produce mechanical effects on objects in their path
What is the typical voltage range required to produce cathode rays in a gas-discharge tube?
10,000 volts or more
What is the direction of travel of cathode rays?
From the negative electrode to the positive electrode
What is the nature of cathode rays?
They are high-speed particles with mass
What is the effect of electric and magnetic fields on cathode rays?
They are deflected
What is a common application of cathode rays?
Generating X-rays
What is the significance of the charge-to-mass ratio of cathode rays?
It is the same for all cathode rays
What is the effect of cathode rays on a pedal wheel?
It rotates
What is the result of cathode rays striking a thin metal foil?
It gets heated up
What is a characteristic of cathode rays in a gas-discharge tube?
They have a high velocity and produce a shadow
Study Notes
Electron Discovery and Cathode Rays
- The electron was discovered through studies of electricity passage through gases at extremely low pressures in a gas-discharge tube experiment.
- Applying a high voltage (>10,000 volts) across electrodes produces invisible rays, known as cathode rays, that move from the negative electrode to the positive electrode.
Properties of Cathode Rays
- Cathode rays travel in a straight path from the cathode with high velocity.
- They produce a shadow of an object placed in their path.
- Cathode rays produce mechanical effects, such as rotating a small pedal wheel placed between the electrodes.
- They are deflected by electric and magnetic fields, confirming they consist of charged particles.
- Cathode rays produce X-rays when striking hard metals like tungsten, copper, etc.
- They heat up thin metal foils when striking them.
- Cathode rays produce a green glow when striking the glass wall beyond the anode.
- They emit light when striking a zinc sulphide screen.
- Cathode rays penetrate through thin sheets of aluminium and other metals.
- They affect photographic plates.
Charge-to-Mass Ratio of Cathode Rays
- The ratio of charge to mass (charge/mass) is the same for all cathode rays, regardless of the gas used in the tube.
Electron Discovery and Cathode Rays
- The electron was discovered through studies of electricity passage through gases at extremely low pressures in a gas-discharge tube experiment.
- Applying a high voltage (>10,000 volts) across electrodes produces invisible rays, known as cathode rays, that move from the negative electrode to the positive electrode.
Properties of Cathode Rays
- Cathode rays travel in a straight path from the cathode with high velocity.
- They produce a shadow of an object placed in their path.
- Cathode rays produce mechanical effects, such as rotating a small pedal wheel placed between the electrodes.
- They are deflected by electric and magnetic fields, confirming they consist of charged particles.
- Cathode rays produce X-rays when striking hard metals like tungsten, copper, etc.
- They heat up thin metal foils when striking them.
- Cathode rays produce a green glow when striking the glass wall beyond the anode.
- They emit light when striking a zinc sulphide screen.
- Cathode rays penetrate through thin sheets of aluminium and other metals.
- They affect photographic plates.
Charge-to-Mass Ratio of Cathode Rays
- The ratio of charge to mass (charge/mass) is the same for all cathode rays, regardless of the gas used in the tube.
Learn about the discovery of electrons through gas-discharge tube experiments and the properties of cathode rays, including their velocity and path.
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