Alevel经济考点解析——汇率
2020年1月新冠疫情在我国爆发，短短几天之内感染人数迅速增加。 为应对病毒的传播和蔓延，武汉市首先采取了封城的措施，随后，受新冠病毒影响严重的省市也纷纷采取了一定程度的封城措施，这一举措降低了人传人的机率，为我国抗疫工作给予了极大的帮助。然而，病毒的出现也增加了某一商品的需求——口罩，短时间内口罩的需求大增，口罩价格也随之飞涨。 为了应对这一情况，政府对口罩实行了价格管制(price control)，避免了口罩的漫天涨价，但同时，一些反对声音开始出现，并声称不应干预口罩价格，那么口罩该不该涨价呢？ 今天我们就利用Alevel经济学来给同学们分析一下！ …… 在通常情况下，口罩这种商品只是一种普通的正常品(normal good)，即口罩价格上涨，口罩需求量降低；口罩价格下降，口罩需求量就增加。 但在疫情期间，口罩成了每家每户的必需品(necessity)，即口罩的需求价格弹性(price elasticity of demand)变小，口罩价格再上涨，其需求量也不会减少很多，如下图所示： 面对这样的刚需，部分口罩销售者开始伺机涨价，一次性口罩价格涨到5、6元甚至更高，像N95这样的口罩则涨到了接近百元一个。我们知道消费者数量(number of consumers)是移动(shift)需求曲线的一个因素，对口罩需求人数的增加会导致其价格的上涨，如下图所示： 需求增加导致在原有价格水平下出现短缺(shortage)，即需求量大于供给量，这样供小于求的状况会拉高市场价格，造成口罩价格的上涨。 不过，我们也知道，市场有调整回均衡状态的机制，口罩的涨价难道通过市场的自发调节不能回归正常价格吗？ 当口罩价格上涨后，口罩生产者就会增加口罩的生产，甚至有的企业也加入到生产口罩的行列(number of suppliers)，从而在高价卖出赚取更多的利润。 这样做的结果就是，口罩的供给就会增加，而供给的增加会最终解决短缺的问题，口罩价格也会随之降低。 这么看似乎市场是万能的，政府没必要惩罚抬价的口罩生产者，但是现实情况却是这些发国难财的商家都受到了不同程度的处罚，难道政府的官员不懂经济学？ 其实不然，我们在分析口罩价格下降的过程时忽略了一个重要的因素——时间(time)，而时间也是影响供给的重要因素：时间越长，供给增加的越多；时间越短，供给增加的越少。 在疫情之下，企业都停工停产，员工也不能正常上班，短期之内口罩的供给不可能迅速增加，从而降低价格，这就是为什么政府一定要干预市场价格，设置一个低于市场价格的最高价格(price ceiling)。当然，从道德上来说，涨价也应该被制止。
A-level考试培训
New
A-level OPENS
A-level预习
A-level
课程亮点
1
爱德思和AQA注册认证的考培中心
2
顾问1V1全方位指导，制定专属学习计划
3
使用原版教材和九天独家辅导资料
4
实体教学环境，沉浸式高效学习
学科
经济类
经济学、会计、商务
自然科学类
物理、化学、生物、科学
人文社科类
地理、历史、心理学、社会学
数学及计算机类
数学、高等数学、计算机科学
语言类
英文文学、英文语言、雅思
课程适合人群
1
适用阶段
（1）欲就读于英国或英联邦体系国际学校A-level阶段的学生
（2）有英语基础但对A-level认识不够全面的学生
A-level OPENS
2
学习收获
（1）课前顾问对学生学习能力1对1评估，量身打造课程，帮助学生充分完成课前预习
（2）课中导师双语沟通，对原版教材进行知识点精讲，帮助学生提前适应国外上课方式
（3）课后完成多样化作业并进行学术测试，班主任线上线下24小时答疑
A-level OPENS
Alevel经济考点解析——汇率
汇率又称外汇利率，外汇汇率或外汇行市，指的是两种货币之间兑换的比率，亦可视为一个国家的货币对另一种货币的价值。具体是指一国货币与另一国货币的比率或比价，或者说是用一国货币表示的另一国货币的价格。今天未来小编就带大家一起来详细解析一下Alevel经济考点中有关汇率的概念内容，希望对大家有所帮助。 1.definition定义 Nominal exchange rate名义汇率: This is the weight of one currency relative to another,withoutbeing adjusted for inflation. Real exchange rate实际汇率: This is when the exchange rate is adjusted for inflation to give a moreaccurate reflection of purchasing power. Trade-weighted exchange rate贸易加权汇率: This is the weighted average of the exchange rate,of thedomestic currency relative to foreign currencies,where theweight of each currency is equalto the share in trade.The more the domestic country trades with a foreign country,thegreater the weight of the currency. 2.The determination of exchange rates汇率的决定因素 Floating exchange rate浮动汇率由供需决定: The value of the exchange rate in a floating system is determined by the forces of supply and demand. Fixed exchange rate固定汇率由government决定: A fixed exchange rate has a value determined by the government compared to other currencies. Managed float exchange rate管理浮动汇率（介于以上二者之间，自由浮动，但是也有governments的干预）: This occurs when the exchange rate floats on the market,but the central bank of the country buys and sells currencies to try and influence their exchange rate. 3.Depreciation and appreciation汇率的升值与贬值 Depreciation贬值:when the value of a currency falls relative to another currency,in a floating exchange rate system. Appreciation升值:when the value of a currency increases.Each pound will buy more dollars,for example. 4.The factors underlying changes in exchange rates影响汇率变化的因素 1.Inflation通货膨胀: A lower inflation rate means exports are relatively more competitive.This increasesdemand for the currency.This causes the currency to appreciate. 2.Interest rates利率: An increase in interest rates,relative to other countries,makes it more attractive toinvest funds in the country because the rate of return on investment is higher.Thisincreases demand for the currency,causing an appreciation.This is known as hotmoney. 3.Speculation投机行为: If speculators think a currency will appreciate in the future,demand will increase inthe present,since they believe a profit can be made by sellingthe currency in thefuture.This can cause an increase in the value of the currency. 4.Other currencies其他货币: If markets are concerned about major economies,such as the EU,the currency might rise.This happened with the Swiss Franc in 2010 when markets were worried about the EU economy. 5.National debt国债: A government with a high level of debt is at risk of defaulting,which could cause thecurrency to depreciate.This is since investors start to lose confidence in theeconomy,so they sell their holdings of bonds. 6.Balance of payments国际收支: When the value of imports exceeds exports,there is a current account deficit.Countries which struggle to finance this,such as through attracting capital inflows,have currencies which depreciate as a result. 7.International competitiveness国际竞争力: An increase in competitiveness increases demand for exports,which increasesdemand for thecurrency.This causes an appreciation of the currency. 8.Government intervention政府干预: Governments might try and influence their currency,such as by maintaining a fixedexchange rate. 5.The effects of changing exchange rates on the domestic and external economy汇率变化对于国内外经济的影响 1.Marshall-Lerner condition and the J-curve effect 马歇尔勒纳条件和J曲线效应（西方汇率理论中的一项重要内容） The Marshall-Lerner condition states that a devaluation in a currency only improves thebalance of trade if the absolute sum of long runexport and import demand elasticities isgreater than or equal to 1. 解释：若想通过汇率贬值改善贸易平衡，则需满足一个条件：即进出口的需求弹性之和必须大于1. The J-curve effect occurs when a currency is devalued.Since devaluing the currency causesimports to become more expensive,at first the total value of imports increases,which worsens the deficit.Eventually,the value of exports increases,which leads to a reduction inthe trade deficit. When the currency is devalued,there may be a time lag in changing the volume of exportsand imports.This could be due to trade contracts and the price inelasticity of demand forimports in the short run,whilst consumers search for alternatives.In the long run,consumers might start purchasing domestic products,for example,which helps improve thedeficit. J曲线效应解释： 当货币贬值时，经常账目赤字不会马上改善，反而会先恶化一段时间。因为当货币贬值时，进口商品会变得更贵，因此进口总额增加，经常账目反而会恶化。 长期来看，货币贬值使得出口商品价格下降，因此出口总值会增加。此外，进口商品价格上升，消费者对于进口商品的需求也会下降。这两个因素使得current account deficit经常账目赤字得以改善，甚至变成current account surplus。 2.The effect of exchange rates on AD 汇率对于总需求的影响 Exchange rate affects AD because they affect the price of exports and imports.If theexchange rate appreciates,AD is likely to fall since imports become cheaper and exportsbecome more expensive. 以上就是小编对于Alevel经济考点中汇率内容的解析。一国外汇行市的升降，对进出口贸易和经济结构、生产布局等会产生影响。汇率是国际贸易中最重要的调节杠杆，汇率下降，能起到促进出口、抑制进口的作用。大家在Alevel经济学习中如果还有什么疑惑，欢迎随时咨询我们！
