Question

The $14\times {{10}^{15}}$ electrons each the anode per second. If the power consumed is $448$ milliwatts, then the plate (anode) voltage is
A. 150$$$$V
B. $200$ $V$
C. 14\times 448$$$$V
D. $448/14$ $V$

Answer 1

The terms anode and cathode are defined by the direction of current through the electrode rather than the voltage polarity of the electrodes. An anode is an electrode that allows conventional current (positive charge) to flow into the device from an external circuit, whereas a cathode is an electrode that allows conventional current to flow out of the device.

Complete step by step answer:
A plate, also known as an anode in the United Kingdom, is a type of electrode that is used in vacuum tubes. It is typically made of sheet metal and is connected to a wire that runs through the glass envelope of the tube to a terminal in the tube's base, where it is connected to an external circuit. A positive potential is applied to the plate, and its function is to attract and capture the electrons emitted by the cathode.

The plate must dissipate heat generated when electrons collide with it at high speeds after being accelerated by the voltage between the plate and cathode. The plate dissipates the majority of the waste power generated in a vacuum tube. In low power tubes, it is usually coated in black and has "fins" to help it radiate heat.

It is frequently made of a refractory metal, such as molybdenum, in power vacuum tubes used in radio transmitters. And is a component of a large heat sink that projects through the glass or ceramic tube envelope and is cooled by radiation, forced air, or water.

The electric power in watts associated with a complete electric circuit or a circuit component represents the rate at which energy is converted from the electrical energy of moving charges to another form, such as heat, mechanical energy, or energy stored in electric or magnetic fields. The power of a resistor in a DC circuit is given by the product of the applied voltage and the electric current.
$P=Vi$

\Rightarrow V=\dfrac{448\times {{10}^{-3}}}{14\times {{10}^{15}}\times 1.6\times {{10}^{-19}}} \\\ \therefore V=200~V$$ Thus, plate (anode) voltage is $$200~V$$. **Hence, the correct answer is option B.** **Note:** An electric circuit has the ability to transfer power. Current is the rate at which charge flows, and voltage is the amount of energy transferred per unit of charge. When the anode potential is greater than the cathode potential, the anode-cathode voltage is said to be "positive," and when it is less than the cathode potential, it is said to be "negative."