OCR GCSE物理 公式表 波速 电路 实验误差
OCR 的 GCSE 物理有两份并行考纲, 一份是 Physics A (Gateway Science, 代码 J249), 另一份是 Physics B (Twenty First Century Science, 代码 J259)。两份都是线性考试, 各含 2 份笔试卷, 每卷 90 分、1 小时 45 分钟、各占 50%, 分 Foundation (卷 01 与 02, 给 5 到 1 分) 和 Higher (卷 03 与 04, 给 9 到 4 分) 两个层级, 学生只能选一个层级考完两卷。刷真题之前先确认自己考的是哪一份, 因为两套卷子的章节顺序、出题语境和分值分布并不通用, 拿错卷子练一个月, 对要考的那一份帮助很小。
OCR runs two parallel GCSE Physics specifications, J249 (Gateway Science, Physics A) and J259 (Twenty First Century Science, Physics B). Both are linear, with two written papers of 90 marks and 1 hour 45 minutes each, weighted 50 per cent apiece and offered at Foundation (papers 01 and 02, grades 5 to 1) and Higher (papers 03 and 04, grades 9 to 4). Confirm which specification your school enters you for, because chapter order, question contexts and mark distribution do not transfer between them.
J249 的八个主题和 J259 的八章不是同一张地图
J249 的官方目录是 P1 Matter、P2 Forces、P3 Electricity、P4 Magnetism and magnetic fields、P5 Waves in matter、P6 Radioactivity、P7 Energy、P8 Global challenges, 另加 P9 Practical skills 贯穿全部内容。P8 下面还分三块: Physics on the move、Powering Earth、Beyond Earth, 讲的是交通、发电与太空探索里的物理, 题面常带表格和短文。J259 走情境路线, 六章主题内容加一条 Ideas about Science 主线, 试卷分 Breadth 与 Depth 两份。很多学生以为两份卷子只是标题不同, 拿 J259 的真题去补 J249 的 P8, 结果练的题型和情境全对不上, 白花两周。
J249 lists eight teaching topics, P1 Matter through P8 Global challenges, with P8 split into Physics on the move, Powering Earth and Beyond Earth, plus P9 Practical skills running through all of them. J259 instead takes a context-led route with six themed chapters, an Ideas about Science strand, and papers split into Breadth and Depth. Papers from one specification are not a substitute for the other, and mixing them up can waste a fortnight of revision.
Paper 1 只到 P4, Paper 2 默认前四个主题已经会了
按 OCR 官网的 specification at a glance, Paper 1 只考 P1 到 P4 加 P9, Paper 2 考 P5 到 P8 加 P9, 但明确写着 assumed knowledge of topics P1-P4, 而且 02 与 04 两份卷含 synoptic assessment。学生常把 Paper 2 当成孤立的后半本书, 复习时把运动图和能量计算放到一边, 到了 P8 的题里需要先用 P2 的运动学再套 P7 的能量公式, 就卡在第一步。合理排法是两轮复习都从 P1 打到 P8, 第二轮重点放在跨主题的题上, 而不是把 P3 电路和 P6 放射性当成互不相干的章节分开背。
According to OCR's specification at a glance, Paper 1 examines P1 to P4 plus P9 while Paper 2 examines P5 to P8 plus P9 and states assumed knowledge of topics P1 to P4, with papers 02 and 04 carrying synoptic assessment, so a plan that treats Paper 2 as an isolated second half of the book strands students when a Global challenges question needs velocity from P2 before an energy calculation from P7; both revision rounds should sweep P1 to P8, with the second aimed squarely at those cross-topic links.
2026 年卷子附公式表, 考点从背公式挪到了选公式
DfE 与 Ofqual 已确认, 2025、2026、2027 三年的 GCSE Physics 与 Combined Science 考试会随卷提供修订后的 data 与 equation sheet, 以插页形式发给考生, 里面包含考纲中的全部物理公式, 这一安排写在 OCR 官网的 subject update 里。常见的错误是把这张表当成保险, 平时不再练变形, 考场上认得出公式却算不下去, 尤其是变压器匝数比、液体压强、导体受力这类需要移项的式子。表不会告诉学生哪道题该用哪一条, 也不会替学生移项, 所以练习重点要从默写公式换成读题选式、移项、代入三步, 每道计算题都逼自己写出符号形式再代数字。
The DfE and Ofqual have confirmed that GCSE Physics and Combined Science exams in 2025, 2026 and 2027 carry a revised data and equation sheet as an insert listing every equation in the specification, as set out in OCR's subject update, yet the sheet never says which relation a question wants and rearranges nothing for the candidate, so the practice that pays is writing the symbolic form first and changing its subject before any numbers appear, particularly for the transformer turns ratio, pressure in a liquid column and force on a conductor.
单位是免费的验算器: 从 m/s 反推 v 等于 s 除以 t
把答案的单位写出来, 再和题目要求的量对一遍, 很多公式不用背也能推。速度单位是 m/s, 也就是 m 除以 s, 对应关系就是 v = s / t; 密度单位是 kg/m3, 对应 m / V; 压强单位是 N/m2, 对应 F / A。一辆车 12 s 内走过 240 m, 平均速度 240 / 12 = 20 m/s; 如果距离错写成 24000 (cm 没换), 答案变成 2000 m/s, 一眼就知道不对劲。代入前把 cm、mm、g 换成 m 和 kg, 把 mA 换成 A, 把分钟换成秒, 这类错在计算题里占的比例比想象中高, 而且一旦单位错, 后面全部步骤都白算。
Writing the unit of the answer and matching it to the quantity asked often rebuilds a formula without memorising it, since speed in metres per second is metres divided by seconds, density in kilograms per cubic metre is mass over volume and pressure in newtons per square metre is force over area, which is why a car covering 240 m in 12 s must average 20 m/s while the same distance left in centimetres returns 2000 m/s and fails the sanity check at once; convert centimetres, millimetres, grams, milliamps and minutes before substituting and that whole category of lost marks disappears.
电路题的代数错误, 多半死在串并联判断上
串联时电流处处相同、电压分配, 并联时电压相同、电流分配, 这两句判断错了, 后面的 R = V / I 一定连带错。6 V 电源接 2 Ω 与 4 Ω 串联, 总电阻 6 Ω, 电流 1 A, 2 Ω 上分到 2 V, 4 Ω 上分到 4 V, 加起来正好等于电源电压; 谁电阻大谁分到的电压多。换成 3 Ω 与 6 Ω 并联接在 6 V 上, 两支路电流分别是 2 A 与 1 A, 总电流 3 A, 等效电阻 2 Ω, 比任何一条支路的电阻都小。阅卷时见得最多的是把并联电阻直接相加成 9 Ω, 再拿 6 V 去除, 得到一个比真实电流小三倍的答案。
In series the current is the same everywhere and the voltage divides, with the larger resistance taking the larger share; in parallel the voltage is the same and the current divides, and the equivalent resistance is smaller than any branch. A 6 V supply across 2 ohm and 4 ohm in series gives 1 A, with 2 V and 4 V across the resistors. Putting 3 ohm and 6 ohm in parallel instead takes 2 A and 1 A, so 3 A in total and 2 ohm equivalent. Adding parallel resistances as if they were in series is the classic slip.
两千瓦的取暖器开三小时, 是 6 kW·h 不是 6000 J
功率乘时间得到能量, 前提是单位配套: W 乘 s 得到 J, kW 乘 h 得到 kW·h。一台 2000 W 的取暖器连续工作 3 小时, 消耗 2 kW 乘 3 h, 也就是 6 kW·h; 按 1 kW·h = 3.6 MJ 换算, 等于 21.6 MJ, 即 2.16 乘 10 的 7 次方焦耳。很多学生以为 2000 乘 3 得 6000 J 就写完了, 数量级差了一万倍, 这种答案在按区间给分时直接判错。电费题还会给出每 kW·h 的单价, 换算时先要把瓦改成千瓦, 再把小时数乘上去, 最后才乘单价, 顺序颠倒很容易漏掉一步。
Power multiplied by time gives energy only when the units agree, so watts with seconds return joules and kilowatts with hours return kilowatt hours at 3.6 MJ each, which is why a 2000 W heater running three hours uses 6 kWh, or 21.6 MJ, or 2.16 times 10 to the seventh joules, while multiplying 2000 by 3 and writing 6000 J lands four orders of magnitude out and loses whatever cost question follows.
波速题的数字不难, 难在频率的单位
v = f 乘波长 是波这一章最常考的关系, 代入前先看频率给的是 Hz、kHz 还是 MHz。声波频率 250 Hz、波长 1.36 m, 波速就是 340 m/s, 这个组合在真题里反复出现; 换到水中, 频率不变而波速变大, 波长跟着变长, 题目常拿这一点做对比。无线电题给 100 MHz, 必须先写成 1.0 乘 10 的 8 次方 Hz 再乘波长, 直接拿 100 去乘会得到小六个数量级的答案。另外要分清周期与频率: 周期 0.004 s 对应频率 250 Hz, 两者互为倒数, 题目给哪一个就用哪一个, 不要自己再换算一遍。
The relation v = f times wavelength appears in almost every waves question, and the trap sits in the frequency unit rather than the arithmetic. A sound wave of 250 Hz with a wavelength of 1.36 m travels at 340 m/s, a pairing that recurs across past papers, while a radio question quoting 100 MHz needs 1.0 times 10 to the eighth hertz before multiplying. Period and frequency are reciprocals, so 0.004 s means 250 Hz.
斜率与面积: 运动图和波动图用的是同一套读图动作
距离时间图的斜率是速度, 速度时间图的斜率是加速度、图线下的面积是位移, 曲线段要画切线取瞬时值。一辆车 4 s 内从静止匀加速到 8 m/s, 加速度 8 / 4 = 2 m/s 每秒, 这 4 s 内走过的距离是三角形面积 0.5 乘 4 乘 8 = 16 m; 如果图线先升后平, 就要把梯形或者几块面积分开加。错得最多的是把速度时间图当距离时间图读, 直接报 8 m, 或者把斜率算成 8 乘 4 而不是 8 除以 4。写答案时把坐标轴单位一并标出来, 读错轴的问题当场就能发现。
On a distance-time graph the gradient is speed, on a velocity-time graph the gradient is acceleration and the area beneath the line is displacement, curved stretches need a tangent and a line that changes slope needs its area split into shapes, so a car accelerating uniformly from rest to 8 m/s in four seconds has an acceleration of 2 m/s squared and covers the triangular area of 16 m, while reading the same graph as distance-time returns 8 m and drops the marks.
中间步骤提前取整, 是计算题最常见的丢分方式
0.45 kg 的球以 12.3 m/s 运动, 动能是 0.5 乘 0.45 乘 12.3 的平方 = 34.0 J。如果先把 12.3 取成 12 再平方, 得 32.4 J, 差 1.6 J, 在按答案区间给分的计算题里通常就是零分。做法很简单: 中间步骤多留两位, 最后一步才按题目要求的有效数字或小数位收尾, 题目没要求就保留两位或三位有效数字。带标准形式的题同理, 1.6 乘 10 的负 19 次方库仑这种量级不要提前约成 2 乘 10 的负 19 次方, 一次粗略取整在乘方之后会被放大好几倍。
A 0.45 kg ball travelling at 12.3 m/s carries 0.5 times 0.45 times 12.3 squared, which is 34.0 J, whereas rounding the speed to 12 first gives 32.4 J; a 1.6 J gap often falls outside the accepted range. Keep extra digits through the working and round only the final answer to the precision requested. Standard form deserves the same care, since 1.6 times 10 to the minus 19 is not 2 times 10 to the minus 19.
六分 extended response 按 level 给分, 先把物理量摆出来
OCR 的每份物理卷都有一道 6 分的 extended response, 按 level of response 评分, 不是数点给分。评分目标的比例是 AO1 占 40%、AO2 占 40%、AO3 占 20%, 所以只堆定义拿不到最高档, 必须出现应用和评价。写法上先给结论, 再用两三条带公式或数据的依据支撑, 最后写一句取舍或局限, 比如测量中散热会让效率被低估, 或者摩擦力让测得的加速度偏小。空着不写是最亏的, 写对一个物理关系就往上进一档, 六分的题写三行也比空白强。
Each OCR physics paper contains a six-mark extended response marked by level of response rather than point by point, and the assessment objectives are weighted AO1 at 40 per cent, AO2 at 40 per cent and AO3 at 20 per cent, so a heap of definitions cannot reach the top band. State a conclusion, back it with two or three pieces of evidence carrying equations or data, then name one limitation such as heat loss making efficiency look lower than it is. An almost empty answer scores nothing at all.
P9 撑起 15% 的分, 考的是变量控制和重复读数
OCR 的 P9 Practical skills 对应试卷中 15% 的实践内容, 学生至少要完成八个规定的实验活动。题目很少直接问结论, 而是问哪个量要控制不变、为什么同一组读数要重复三次、某个明显偏离的数据点该怎么处理, 或者某张装置图里哪里会让结果偏大。答题时把自变量、因变量、控制变量分别点名, 比写一句保持条件相同得分高, 例如测电阻随长度变化时, 要写明温度、材料和横截面积保持不变。误差也要分开说: 随机误差靠多次测量取平均, 系统误差要靠校准仪器或改方法。
P9 Practical skills accounts for the 15 per cent of marks tied to practical work and students complete at least eight required activities, yet the questions rarely ask for a conclusion, preferring to test which quantity must stay constant, why readings are repeated three times or what to do with an obvious outlier, so naming the independent, dependent and control variables explicitly beats any promise to keep conditions the same, and random error is answered by averaging while systematic error needs calibration or a changed method.
分数线告诉你该争哪几分: 2026 年 6 月 J249 Higher 的 9 分线是 152
OCR 公布的 2026 年 6 月 J249 分数线里, Higher 满分 180, 9 分线 152 分 (84.4%), 7 分线 131 分 (72.8%), 4 分线 80 分 (44.4%); Foundation 的 5 分线是 123 分 (68.3%), 4 分线 108 分 (60.0%)。这意味着 Higher 上 7 到 9 之间只有 21 分左右的空间, 单位、有效数字、六分题这种能稳定拿到的分比压轴题更值钱, 一道两分的单位题抵得上压轴题的一小问。按 90 分对 105 分钟算, 每分约 1.2 分钟, 六分题留 7 分钟, 剩下时间回头查单位和小数点。
In OCR's published boundaries for the June 2026 J249 series, the Higher tier is out of 180 with grade 9 at 152 marks (84.4 per cent), grade 7 at 131 (72.8 per cent) and grade 4 at 80 (44.4 per cent), while the Foundation grade 5 boundary sits at 123 (68.3 per cent). With roughly 21 marks between grades 7 and 9, dependable marks in units, significant figures and the six-mark question outweigh the hardest item on the paper, and 90 marks in 105 minutes means about 1.2 minutes per mark.
复习顺序可以按卷子倒推: 先把 P1 到 P4 的计算和图线练到不看公式表也能下手, 再把 P5 到 P8 的代入练熟, 然后用两套完整真题各限时做一遍, 对着分数线估自己的位置, 最后把错题按单位、读图、选公式、表述四类归档。公式表会随卷发下来, 但选哪条公式、单位怎么换、依据怎么写, 卷子不会替学生做。
A workable order runs backwards from the papers: make the calculations and graphs in P1 to P4 fluent without the sheet, drill substitution across P5 to P8, then sit two full past papers under time and compare the totals against the published boundaries, sorting every mistake into units, graph reading, equation choice or explanation. The equation sheet arrives with the paper, but choosing the relation, converting the units and justifying the answer stay with the candidate.
Cambridge International AS ALevel Physics Coursebook 正版剑桥国际AS ALevel考试物理教材带线上账号 英文原版¥557.0📱 去京东购买京东精选
需要一对一辅导？Need One-on-One Tutoring?
A-Level / GCSE / IB / KS2-KS3 全科辅导
16621398022 同微信
Visit aleveler.com
或截图后用「扫一扫 → 相册」选择本图