// JavaScript Document
thepage="Wavelength, Frequency, Energy"
//globals
refnumber=9
//updated 12/02/02-netscape 7
attempts=0
theanswer=""
answered=0
theanswer1=""
theanswer2=""
whichone=""
valE=0
valfreq=0
valwave=0
sol=3.00+"*10<sup>10</sup>cm/sec"
pc=6.626+"*10<sup>-34</sup>J-sec"
function parts(p1,p2,p3,p4,p5,p6,p7,p8){
	this.p1=p1
	this.p2=p2
	this.p3=p3
	this.p4=p4
	this.p5=p5
	this.p6=p6
	this.p7=p7
	this.p8=p8
}
showit=new Array(5)
corrt=totl=0
whichphrase=0
theanswer=""
needed=new Array(5)
needed[1]="wavelength"
needed[2]="frequency"
needed[3]="energy"
missing=new Array(5)
formula=new Array(5)
formula[1]="freq=c/wavelength<br>E=h*freq"
missing[1]="frequency and energy"
formula[2]="wavelength=c/freq<br>E=h*freq"
missing[2]="wavelength and energy"
formula[3]="freq=E/h<br>wavelength=c/freq"
missing[3]="frequency and wavelength"
known=new Array(5)
ansphrase=new parts("This problem deals with the following relations:<br>freq=c/wavelength;E=h*freq<br>Organize your data, identifying the given and the unknowns:<br>wavelength=","<br>frequency=","<br>energy=","<br>Since you need to calculate ","</b>, arrange the above equations, as appropriate:<br> ","<br>Substitute in the values and perform the calculation:")

//This function clears all values in both tables on loading the page
//This function clears the first table
function clear(){
	document.forms[0].first.value=""
	document.forms[0].second.value=""
	document.forms[0].third.value=""
	tried=0
	clearansspot()
}
//This is the function started when "New Problem" is pushed	
//This function first clears all old values using zeroout()
//The three variables(wave,freq,E) are then determined, using Math.random() to 
//generate wave and the known relationship to generate freq and E.
function begin(){
	tried=0
	totl++
	clear()
	h=Math.random()
	if (h<.33){wave=1e-3*Math.random()}
	else{if(h<.67){wave=Math.random()}
	else{wave=1e3*Math.random()}}
	freq=3e10/wave
	E=6.626e-34*freq
	valwave=number(wave,1)
	valfreq=number(freq,2)
	valE=number(E,3)
	problem()
	document.forms[0].total.value=totl
}
function number(a,b){
	if (a>=1 & a<10){
	sign=""
	display(a,sign,0)}
	else{if(a>10){
		sign="+"
		for (var i=1;i<100;i++){
		a=a/10
		if (a<10){
		break}}}
	else {
		sign="-"
		for (var i=1;i<100;i++){
		a=a*10
		if (a>1){
		break}}}
}
a=Math.round(100*a)/100
	if (sign==""){
	a= a}
	else{
		known[b]=a+"*10<sup>"+sign+i+"</sup>"
		a=a + "e" + sign +i
	}
return a}
//This adjusts the coefficient to three sig figures
//and then displays the result.
function display(a,n,sign,i){
	a=Math.round(100*a)/100
	if (sign==""){
	a= a}
	else{
	a=a + "e" + sign +i}
}
//This function creates the problem and the answer method by displaying only
//two of the three variables while passing all three to hidden cells in a hidden
//table
function problem(){
//the following places a value in one of the cells in the first table
//creating the problem
	whichone=Math.ceil(3*Math.random())
	if (whichone==1){
		theanswer1=valfreq
		theanswer2=valE
		document.forms[0].first.value=valwave
		document.forms[0].second.focus()
		document.forms[0].second.select()
		showit[1]=known[1]+"cm"
		showit[2]="?"
		showit[3]="?"
	}
	if (whichone==2){	
		theanswer1=valwave
		theanswer2=valE
		document.forms[0].second.value=valfreq
		document.forms[0].first.focus()
		document.forms[0].first.select()
		showit[1]="?"
		showit[2]=known[2]+"sec<sup>-1</sup>"
		showit[3]="?"
	}
	if(whichone==3){
		theanswer1=valwave
		theanswer2=valfreq
		document.forms[0].third.value=valE
		document.forms[0].first.focus()
		document.forms[0].first.select()
		showit[1]="?"
		showit[2]="?"
		showit[3]=known[3]+"J"
	}
	buildanswer()
}
function buildanswer(){
	if(whichone==1)thefinal=sol+"/"+known[1]+"cm="+known[2]+"sec<sup>-1</sup><br>"+pc+"*"+known[2]+"sec<sup>-1</sup>="+known[3]+"J"
	if(whichone==2)thefinal=sol+"/"+known[2]+"sec<sup>-1</sup>="+known[1]+"cm<br>"+pc+"*"+known[2]+"sec<sup>-1</sup>="+known[3]+"J"
	if(whichone==3)thefinal=known[3]+"J/"+pc+"="+known[2]+"sec<sup>-1</sup><br>"+sol+"/"+known[2]+"sec<sup>-1</sup>="+known[1]+"cm"
	theanswer=ansphrase.p1+showit[1]+ansphrase.p2+showit[2]+ansphrase.p3+showit[3]+ansphrase.p4+missing[whichone]+ansphrase.p5+formula[whichone]+ansphrase.p6+"<br>"+thefinal
}

function screen(){
	if(whichone==1){response1=document.forms[0].second.value
	response2=document.forms[0].third.value}
	if(whichone==2){response1=document.forms[0].first.value
	response2=document.forms[0].third.value}
	if(whichone==3){response1=document.forms[0].first.value
	response2=document.forms[0].second.value}
	answer()
}
function answer(){
	if(tried==1)alert("You've already done this one! Get a new problem!")
	else{
	if(tried==2){totl++
		document.forms[0].total.value=totl
	}
	if(response1>.95*theanswer1 & response1<1.05*theanswer1 &
	response2>.95*theanswer2 & response2<1.05*theanswer2){
	corrt++
	document.forms[0].results.value="correct"
	document.forms[0].correct.value=corrt
	tried=1}
	else {
		tried=2
		document.forms[0].results.value="incorrect"
	}
}}