Redefining the Kilogram

The video explores the redefinition of the kilogram, which has been traditionally defined by a physical object in Paris. Due to discrepancies in mass measurements, a new definition based on Planck's constant is being developed. The video explains the Kibble balance, a device used to measure Planck's constant with high precision, and discusses the role of quantum effects in this process. The redefinition aims to provide a more stable and universal standard for mass measurement.

Why is the current definition of the kilogram considered problematic?

• It is based on a physical object that can change over time.

• It is too complex to understand.

• It is not recognized internationally.

• It is based on outdated technology.

What is the main goal of redefining the kilogram?

• To make it easier to measure.

• To reduce its weight.

• To base it on a constant of nature.

• To align it with the meter.

Which two methods were primarily considered for redefining the kilogram?

• Using a silicon sphere and a Kibble balance.

• Using a platinum bar and a silicon sphere.

• Using a Kibble balance and a platinum bar.

• Using a silicon sphere and a gold bar.

What is the Kibble balance used to measure?

• The gravitational constant.

• Planck's constant.

• The speed of light.

• Avogadro's number.

In the Kibble balance, what are the two modes of operation?

• Weighing mode and velocity mode.

• Current mode and voltage mode.

• Magnetic mode and electric mode.

• Static mode and dynamic mode.

How is voltage measured accurately in the Kibble balance?

• Using a laser interferometer.

• Using Josephson junctions.

• Using a gravimeter.

• Using a voltmeter.

What quantum effect is used to measure resistance in the Kibble balance?

• Quantum Hall effect.

• Quantum superposition.

• Quantum entanglement.

• Quantum tunneling.

What is the significance of Planck's constant in the new definition of the kilogram?

• It is used to measure temperature.

• It is used to define the meter.

• It is a fixed value that defines the kilogram.

• It is a variable that changes with time.

What device is used to measure the local acceleration due to gravity in the Kibble balance room?

• A gravimeter.

• A voltmeter.

• A barometer.

• A thermometer.

What is the expected outcome of redefining the kilogram in 2018?

• The kilogram will be based on a new physical object.

• The kilogram will be defined by a fixed value of Planck's constant.

• The kilogram will be defined by the speed of light.

• The kilogram will be eliminated from the SI units.