A 120-Ω laboratory resistor is rated at 0.25 W. How much current can safely flow through the resistor?

0.0436 A

Explanation:

Current: This can be defined as the rate of flow of electric charge in a circuit. The S.I unit of current is Ampere (A).

The expression of current is given as

P = I²R

Where P = power, I = current, R = Resistance.

Make I the subject of the equation,

I = √(P/R) Equation 1

Given: P = 0.25 W, R = 120 Ω

Substitute into equation 1

I = √(0.25/120)

I = √(0.00208)

I = 0.0456 A.

Hence the current that can safely pass through the resistor = 0.0436 A

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz

f=ma newton

f=100x2.5=250n